The Diffy family — Barbara, Lloyd, Phil, and Pim — are your average 22nd century family. Which is a lot like your normal Nuclear Family, except with aliens. During their vacation through time, their time machine breaks down in the present day. The family must rough it out in the 21st century while trying to get back home — all the while not telling anyone that they're from the future. (Well, anyone except Keely Teslow, Phil's 21st century love interest.)This is a Disney Channel show, which of course means one of the girls sings for the Disney Records label. (In this case, Alyson Michalka, who plays Keely, teams with her younger sister A.J. to form the pop group Aly & AJ (Now known as 78violet.)This is the last Disney Channel Original Series to date not to be produced by It's A Laugh Productions, which almost certainly explains why it was cancelled after a mere 43 episodes, in favor of all the other shows that were. It lasted from 2004 to 2006.
The Alternet: Phil introduces Keely to the Giggle, "the thing, that replaced the thing, that replaced the thing that killed the Internet in a pay-per-view battle royal" in the future Phil hails from. It's a helmet with a screen on it that contains all of mankind's knowledge up to 2121 and constantly updates itself when information changes.
Artistic License - Physics: In "Good Phil Hunting", Pim can (apparently without the use of any gadgets) build up enough of a static charge to go all Emperor Palpatine on anyone who touches her. Pim being Pim, she ends up using it to get revenge on Candida.
To add to that, Doug Tuber (one of the creators) confirms that he and his writing partner Tim Maile (The other creator) were hired by Disney to write the Phil of the Future finale movie. Doug say's it was a very detailed and funny and romantic outline. Disney decided not to produce it.
Egg Sitting: Pim gets paired up with her enemy to take care of a sack of flour. They figure it's an easy A (because a sack of flour doesn't do much) until Barb insists they treat it like a real child. Hilarity Ensues as she and her partner start arguing over their fake relationship issues and how to raise their "child." They eventually end up in a tug-of-war over the flour sack and burst it all over the school hallway...just as the teacher walks by.
Failure Is the Only Option: Lloyd purposefully procrastinated/sabotaged the systems because the family enjoyed the 21st century so much. He really could've just fixed it at any time.
Fate Drives Us Together: Implied with Phil and Keely at several points, including Keely placing her childhood music box into the school's time capsule that is later found by Phil's mother and used when he was a baby.
High School: Most of the scenes take place at school. Unusual in the fact that it's a junior/senior high school; Phil and Pim attend the same school despite Pim starting off the series in 7th grade and Phil in 9th.
Holding Hands: Phil Diffy and Keely in the finale episode "Back To The Future (Not The Movie)". The irony is that they've probably held hands a million times before as friends, but once they decide to become a couple, they can't get the logistics right.
Idol Singer: Aly & AJ (Now known as 78violet), one half of which is the show's female lead, Alyson Michalka.
It Runs On Nonsenseoleum: Milk engines were invented in 2075 after oil ran out. This causes issues when Phil enters one in a science fair in 2004, well before it was invented and Phil has no proof that he'd designed it. It's alluded to in a Continuity Nod when Lloyd remarks in a flashback that a ringing landline phone sounds like a robot is out of cheese.
No alloy in existence can jam a Wizard's signal, except for pudding. They're defenseless against pudding.
Large Ham: The guy who plays Messerschmitt quite obviously has way too much fun with every single line he says, especially in "The Giggle" when discussing the Omicron Gambit, his legendarily hard...make-up test. It's all Played for Laughs, of course.
Married In The Future: In "The Giggle," Phil uses a future gadget to look up Keely's future as a journalist, after they fail a huge test in school and take a re-test. In the first future, Keely is a crazy cat lady who is convinced one of her cats was abducted by a UFO. In the second future, she's a reporter...and (as the young Keely notices) she's wearing a wedding ring. It's never revealed who her husband is in the future and Keely stated that she'd rather wait for the surprise than use the gadget to look it up. But given the massive amount of Ship Tease in the series as a whole, it's heavily implied that it's Phil.
The Matchmaker: Keely in "Stuck in the Meddle with You." And it's said she's done it before...with unfavorable results.
May-December Romance: Accidentally and played for laughs in "Age Before Beauty". When Keely ages herself with a future device and catches the romantic attention of Vice Principal Hackett, Phil must step in and pretend to be her boyfriend to deter him. Unfortunately, he accidentally ages himself to about 80, to Keely's 20-something.
Meet Cute: Phil and Keely, though Keely didn't know. The entire episode "Christmas Break" is devoted to how they met. Keely was the Pickford Yuletide Star Princess in charge of the town's yule star (obviously) to be used in a tree lighting ceremony. Pim breaks the glass Yule star, and Phil, feeling badly about it, goes back in time to fix it. Through a series of unfortunate events, he ends up going back in time several times to save the star, eventually succeeding. Keely finds this sweet, Pim...not so much:
Keely (about the Christmas tree star): Ooh, that's my favorite part.
Phil: I know, you were the Pickford Yuletide Star Princess, after all.
Keely: That's right! Wait...we didn't even know each other then. How did you know about that?
Phil: Well...you see...I actually met you before you met me.
Pim: Met her? You followed her around like a pathetic puppy.
Pim: He was like 'Oh, we have to help the pretty crying girl!'
Puppy-Dog Eyes: Keely gives these to Phil in episode “Age Before Beauty”, "The Giggle" and "Dinner Time".
Put on a Bus: Tia, Bradley Benjamin Farmer, Debbie, and Seth Wassmer.
Race for Your Love: Phil and Keely end up doing this in the final episode, though with far different results. Keely suddenly changes her mind about seeing Phil and his family back to the future and runs to catch their time machine before it leaves. She's unsuccessful. The second time is Phil, who has his father return their time machine to about five minutes before Keely does her race and he catches her at school to say goodbye (cue The Big Damn Kiss)
Red Stringof Fate: Played with with Phil and Keely. In "Time Release Capsule", Keely puts her own childhood music box in the school's time capsule; Phils mom finds it a century later and plays it for him as a baby. It's revealed in "Christmas Break" that Phil was the one who broke the time machine, but that if he hadn't stopped to help Keely, the family would have been caught in a massive time-storm and gotten lost forever.
Reed Richards Is Useless / Plot Technology: Justified, since they have to maintain the masquerade and minimize their impact on the outcome of history, they can only use the future tech to solve the day's problems.
Relationship Upgrade: Phil and Keely in the season 2 finale which ended up being the series finale "Back To the Future (Not The Movie)".
The Rival: Bradley Benjamin Farmer and Candida are rivals of Pim.
School Clubs Are Serious Business: H.G. Well's budget for extracurriculars is astronomical and the level of seriousness given is hilarious. Pim hosts a tele-a-thon in one episode to "find a cure" for the science club's pet rat. Keely goes undercover in another episode to write a story on dirty mop water for the school news station.
As well, in "Good Phil Hunting", Hackett is briefly shown writing equations on a clear, glassy surface, mimicking similar memorable moments from A Beautiful Mind and Good Will Hunting.
In the same episode, Hackett asks Phil what the first rule of AV club is. Naturally, it's "Don't talk about AV club." There's also a reference to Fermat's Last Theorem; apparently a problem known as Foucalt's Last Conundrum is highly difficult in the present day, but is basic material in 2121's third grade.
When Mr. Hackett wakes up from the shock of Keeley "solving" said Conundrum:
In "Dinner Time", Barb's trying to prepare a typical American dinner party. Her research leads her to believe that it should be 50's style, right down to the clothes. Phil ends up looking like Fonzie, right down to flashing the classic double thumbs up right after being zapped with the Wizard and immediately lampshading it.
"Dinner Time" also slips in a reference to The Wizard of Oz, when a pair of prospective buyers for the Diffy house ask if it has suffered a twister of "Oz or greater magnitude".
Worthless Yellow Rocks: Diamonds are a waste product in the future, but aluminum foil is apparently invaluable.
Very much justified. Aluminum is valuable even today (which is the motive behind pop tab collections), while diamonds are easily manufactured from common carbon.
While it makes sense for diamonds to be dirt cheap in the future, it does not make sense for them to be a waste product. Diamonds are useful cutting tools due to their unparalleled hardness. The only way they would become garbage is if someone invented a synthetic mineral that was even harder than diamond and at least as cheap.