Awesome / Harry Potter and the Prisoner of Azkaban
Hermione slapping Draco in the face. Little twerp had it coming...
And then driving Draco (who, remember, never hesitates to toss a taunt or racial slur her way) into full retreat by merely pulling out her wand. It suddenly occurred to him that he's just pushed the most talented witch in the school one inch too far.
Ron has had his leg broken by a deranged murderer (he is led to believe) and can basically be defeated by a stiff wind. So he tells that same murderer, while standing on said broken leg, probably through excruciating pain, placing himself between them, if he wants Harry, he'll have to go through him.Steve Kloves can be safely ignored on this front: Ron is Harry's man, through and through.
An easily missed example of this is when the Grim, really Sirius,attacks Harry, Ron, and Hermione to get at Pettigrew. Out of the three, Ron has been the most superstitious about the Grim throughout the whole book. So what does he do when he sees a massive dog that looks like a Grim attack Harry? He instantly gets to his feet and pushes Harry out of the way, letting the Grim take him instead.
Expecto Patronum! A lone 13-year-old boy against more than a hundred soul suckers. The boy wins.
The Quidditch Final.
Definately, Oliver finally gets to finally hold the award he has wanted and been denied every book previously.
The entirety of the Shrieking Shack scene.
"The Marauder's Map never lies. Peter's alive, Harry. Ron's holding him."
"I want to finally commit the murder I was imprisoned for!"
"If you want to get to Harry, you'll have to go through me!"
"THEN YOU SHOULD HAVE DIED! DIED RATHER THAN BETRAY YOUR FRIENDS, AS WE WOULD HAVE DONE FOR YOU!"
Boy scoutsthey weren't, but the Marauders - a bunch of teenagers not much older than Harry and his friends were at the time of this book - not only learned the highly advanced process of becoming Animagi (for the sake of a friend, but also created a detailed map of the near entirety of Hogwarts Castle that is also capable of tracking the location of any student that sets foot there. It's stated to work well enough that Harry can use it nearly twenty years after its creation... and implied to still work just as well after nearly another quarter-century, at which point Word of God says Harry's son (fittingly named for two of the Marauders) takes the map for himself. The fact that they innovated such a powerful magical artifact at probably around 16 years old speaks to some great talent.
Death can't see anyone under the Invisibility Cloak. The Marauder's Map can.
Instead of slapping Draco, Hermione straight-up punches him.
Even more awesome considering Harry and Ron had just talked her out of hurting Draco (she had him at wandpoint). She calms down, turns his back on him, Malfoy almost immediately recovers his smug look, and then she turns right back around to clock him right in the face.◊ Malfoy's head even seems to bounce off the brick wall behind him!
Hermione: That felt good.
Ron: Not good...brilliant!
What's more awesome is that the punch fazed Malfoy so much, that he and his colleagues immediatelybooked it. Malfoy then looked back at Hermione donning a look of terror. If that's not awesome, what is? This moment is now easily one of the most iconic of the films.
Snape gets one he never got in the books. Runs out of the Whomping Willow, sees a werewolf about to eat them, and his first response is to stand between the kids and the wolf. Not bad, Snape.
And not long before, Hermione piecing together three or four small bits of information not once, but twice, both in the span of seconds, to create a Stable Time Loop and ensure that what needs to happen happens.
Once, when she beans Harry with an odd-shaped rock she remembers seeing to make him realize that they're about to get caught so they'll leave Hagrid's hut.
And then distracting the werewolfed-out Lupin with a fake call to get him to come towards them instead, because they're in exactly the right place at the right time and a werewolf only responds to the call of another werewolf.
Hermione using the spell 'Bombarda' to dramatically break open Sirius's cell. Bonus for accompanying awesome music.
Sirius whooping as he, Harry, and Hermione fly away from his cell on Buckbeak.
The entire time-travel sequence. Not only do they save Sirius, but they save Buckbeak as well without being seen.
Harry's flight on Buckbeak. Especially the moment when they're flying over a lake and Harry sits up, spreads his arms out, and whoops in joy! Particularly since in the book Harry doesn't enjoy the flight (which is depicted as short, stilted and awkward) at all. It's nice to see him having a chance for a bit of fun.
A Meta example: the extremely minor scene when MacNair, the executioner, eerily grins at Harry when he passes by. Goblet of Fire reveals MacNair to be a Death Eater, adding a new level of depth to the tiny, otherwise inconsequential scene. While MacNair never does anything else in the series notable besides preside over Buckbeak's execution, it's a very coy, Shown Their Work type of Foreshadowing that must be given credit, and may have been unintentional!