The infamous "Guatón de la Fruta" ("Fat Guy of the fruits") that appears in Chilean ads for a brand of fruit juice.
Anime and Manga
Junpei "J.P." Shibayama of Digimon Frontier. Bit of a Dogged Nice Guy. Known for his magic tricks and giving of chocolate. He was actually rather friend-less and insecure deep down, as revealed in his backstory, but with some Character Development he fits in better.
Rider( Iskandar/Alexander the Great) in Fate/Zero was this slightly subverted in that he was incredibly muscular instead of fat(he has arms bigger around than most people period). He is easily the largest Servant in terms of both height and general body mass, and at the same time thinks that every new thing in the modern world is just AWESOME and is an avid gamer, naturally(being who he is) he plays strategy games. We can only assume that he was pretty damn good at them too.
Honestly, this guy takes both Boisterous Bruiser and Big Fun to the max, everything he does is specifically meant to be both awesome and fun. Really, it seems that by his definition, for something to BE awesome at all it has to be fun. Take for example the infamous King's Banquet, where he shows up out of nowhere at the Einzburn castle with a literal cask of wine and asks saber to join him in drinking it. He shows up in a T-shirt and jeans while driving a lightning bolt shooting chariot. And he somehow managed to convince Gilgamesh of all people to come too?
A notable subversion was Mondo of Generation X. He seemed at first to be a party animal, fitting this Trope perfectly. As it turned out, he was a spy planted by the villain Black Tom Cassidy, who eventually turned against them. He also wasn't the real Mondo.
Fat Cobra from Immortal Iron Fist is a big eater and womanizer who loves a good fight and is quite friendly.
Films — Animated
Possible subversion: Po the Panda from Kung Fu Pandaacts like this, to mask his insecurity at being the fat oaf at the Furious Five's kung-fu school. He gets more serious as the movie goes along, but is still the nicest guy in the movie.
Inversion: Manny the Mammoth in Ice Age is assumed to be jolly by pretty much anybody who meets him. Anybody who lampshades this trope is promptly informed that: "It's not fat, it's fur. It makes me look... poofy."
PJ develops in this direction in An Extremely Goofy Movie, becoming the center of attention at the disco briefly and spending much of the last part of the film enjoying himself (except for one brief relapse and a moment of peril). Before that point—in the first part of the movie, the predecessor, and the series—he was kind and friendly, but "fun" was not how he would be described most of the time. He was a Nervous Wreck and a Shrinking Violet who was very pessimistic, sometimes downright despondent, not usually enthusiastic, and even when he was it would be subdued compared to those around him with similar goals. The reason for this change? He earned his happy ending.
In Remember the Titans, Louie is the first to easily break racial tension, and can crack a joke or two: "I just gave your mamma a piggy-back ride, and she weighs twice as much as I do!". His actor Ethan Suplee may have been this before he lost 200 pounds.
Best Night Ever has a a female example. Janet is chubby (by Hollywood standards; by normal standards she's average size) and constantly cheerful and bubbly.
Friar Tuck is usually portrayed as this in most versions of the Robin Hood legend.
In the Aubrey-Maturin series, Captain Jack Aubrey has often been chided by Stephen Maturin over his weight. He weighs around 18 stone, which is roughly 250 pounds. Of course, he's also an excellent fighter, which puts him squarely in Stout Strength (and Genius Bruiser, considering his tactical prowess and achievements in astronomy and mathematics) territory. He also loves to party when he has the chance, and he's been known to make an utter fool of himself in social occasions, which makes him a Boisterous Bruiser too. The ladies seem to appreciate it too: He's practically the James Bond of the Napoleonic War era.
King Robert Baratheon. Also a slight deconstruction; as a Boisterous Bruiser put into the role of king and forced into a loveless political marriage after the woman he fought the war for in the first place died, Robert's been unable to exercise most of his appetites (the ones that aren't drinking and whoring), which has led him to grow fat. The jovial humor masks a heavy accumulation of grief, rage, and utter disappointment.
Wyman Manderly is widely seen as this, a massive man who enjoys food, wine, and jests. In A Dance with Dragons, it's shown that this is a ruse; his revenge against the Freys reveals a cunning and ruthless mind behind the merry facade.
Nanny Ogg — a very plump witch who loves food, booze, and music and can even get a date despite having "a face like an elderly apple," because she's that much fun.
Archchancellor Ridcully is one of the few wizard examples; many other wizards are fat and love food, but are do-nothings or actually nasty. Ridcully on the other hand likes sports and jokes and is a Boisterous Bruiser.
Sgakahav "Sig" Wilobst, the owner of the Wilobst Pioneers Ltd mercenary/gun-running firm in Riesel Tales: Two Hunters. He is this to an extreme literal level — his species is, on average, eighteen feet tall, and he has a big, jolly personality to match. Sookaiya Venatosh, one of his mercenaries, is this to a lesser extent.
Live Action TV
Kimmie Boubier from Super Fun Night. The title of that show even supports the trope.
Gordon Crisp on Freaks and Geeks. At one point he and Harris even lampshade the trope.
Gordon: My whole family's big-boned. It's genetic. Harris: Besides, the world loves jolly fat guys. Burl Ives. Jackie Gleason. Gordon: Santa Claus. Curly. Raymond Burr. Neal: No. Raymond Burr isn't jolly. Gordon: Well he was extremely nice to me at last year's auto show.
Paul Baloff, the late lead singer for Thrash Metal band Exodus, fit this trope. Some people even nicknamed him "The John Belushi of Heavy Metal" because of his outgoing, uninhibited, party animal personality.
Fats Domino, of course. His first hit was "The Fat Man."
Most members of Bowling for Soup are at least overweight, and they sing songs about being happy and are sometimes downright silly. Even most of their songs about heartbreak are fairly optimistic and/or funny.
These jolly giants are never cruel. All big people are really cool!
Flash Gordon has Vultan of the Hawkmen. The dude can fly, too! Those are some strong wings!
The gambler in High Roller Casino is a big, beefy Texan (complete with hat) who speaks very bombastically.
As pictured, Budai, also known as Hotei. He fits into both Japanese Shinto and Buddhist traditions, as he's one of the Seven Gods of Fortune in Japanese belief, but also considered to be an incarnation of the future Buddha Maitreya, who will appear in a dark age when the tenets of Buddhism are forgotten and nobody can reach enlightenment - a time where everyone needs a laugh, as you'd imagine. The popular label of "The Laughing Buddha", although it is true that he brings good luck if you rub his belly.
The Dagda of Celtic Mythology. Some religions make their father gods stoic, handsome loving figures. The ancient peoples of Britain and Ireland made theirs a comical, singing, dancing, fat old guy with his arse hanging out of his trousers. And he is awesome.
BFF Nella. She has issues, of course (mostly to do with being abused) but she's a lot happier than the more conventionally pretty, jerkass, Broken BirdNostalgia Chick.
Jon Jafari. Despite being one half of Game Grumps he spends 70% of the show laughing, singing and being generally likeable and fun with his more reserved co-star Arin Hanson (Egoraptor).
Zeke in In FAMOUS. By all accounts, a friendly, easygoing kind of guy. Sadly, his urge to become a superhero results in him betraying Cole later in the game. Thankfully, he recovers in the sequel, becoming a much better friend to Cole in the process.
Sadly, what applies to Zeke above also applies to Smoke.
E Honda in his various adaptations throughout Street Fighter seems to have many friends and allies. Probably due to exactly how seriously he's taking the tournament. As of ''Street Fighter IV, he wants to join the IOC to make Sumo Wrestling an official Olympic sport, he has friendly-yet-serious wrestling matches with Hakan over whether Sumo or Turkish Oil Wrestling is the "better" sport, and he's more than happy to supply El Fuerte with his recipe for Chenko Stew.
Fatman from Metal Gear Solid 2: Sons of Liberty would qualify, except for the detail that his idea of fun is blowing things up with bombs. Still great fun at parties if you check him for C-4 at the door.
Fatman:Laugh, and grow fat!
The Heavy of Team Fortress 2, at least to his own team. To everyone else, he's describable as "a big, shaved bear that hates people."
The Wii version of Punch-Out!! gives us returning challenger Bear Hugger, who, while easily one of the physically widest and most rotund boxers to get in Little Mac's way, is also an entertaining, goofy Boisterous Bruiser with a big laugh, whose lines are pure comic gold, usually playing into his Canada, Eh? stereotype for all it's worth. He also seems to be in it for fun rather than harboring any serious thoughts of contending or being outright Ax-Crazy.
The borderline round Sasquatch from Darkstalkers. It's mostly fluffy fur , but he's got no major issues to deal with involving the other characters of the series. He enjoys making snowmen in the middle of a fight too.
Reagan from Templar, AZ. Besides being a BBW and the owner of a porn shop, she's probably the funnest of all the cast to be around.
Homer: Marge, the boy was wearing a Hawaiian shirt. Marge: So? Homer: There's only two kind of guys who wear those shirts: gay guys and big, fat party animals. And Bart doesn't look like a big, fat party animal to me... Marge: So, if you wore a Hawaiian shirt, it wouldn't be gay? Homer: Right. Thank you.
Daniel Lambert. Despite having worked as a gaol-keeper, he is best described as a nice guy and a loved local figure. It helped that morbidly obese people weren't viewed as harshly in 18th/19th century England as they are now, but are rather regarded as marvels to be seen.
Benjamin Franklin is the quintessential American example. As a junior printer, though, he was in excellent shape from carrying large cases of heavy lead type.
U.S. President William Howard "Big Bill" Taft, known for his appetite and enormous size, was a man with impeccable morals. He was incredibly loyal (some might say blindly loyal) to his friends and his political party. One journalist wrote of him, "He seemed to me an American bison, a kind and gentle one." He was also known for throwing lavish and expensive banquets at the White House.
Andrew Zimmern, the bald and huge host of the show Bizarre Foods. His usual approach to everything in life is with a smile and an optimistic attitude. He'll at least try a food, even if he finds it disgusting. He never gets outright angry or shows incredible disgust for anything. Not even the infamous durian, the only food he absolutely cannot eat (even after trying 3 times, he still couldn't swallow), was enough for him to straight up turn away from.
A lot of rappers seem to cultivate this image. Guys like The Notorious BIG., Fat Joe, and Cee Lo Green (despite only being 5'5") are all pretty heavy and generally seeming like the type of people who knew how to party.
Fitness guru Richard Simmons deconstructed this trope in his first self-help book, Never Say Diet, by way of a true-or-false quiz entitled "Are Fat People Jolly?" Basically, the reader was invited to choose whether or not certain health-related or societal consequences of being overweight were fun to deal with:
Not getting into the college of my choice because of a weight problem is jolly.
Dying twenty years earlier than necessary is jolly.
Being passed over for a job for an equally-qualified candidate of ideal weight is jolly.