The tumbling hallway fight scene. A oner using nothing but strings, a nifty rotating set and brilliant choreography.
The scene where Cobb tells Fischer he's in a dream and the items in the room—but not the room itself—begin to tilt was also entirely practical, using a set on a giant gimbal and careful camera placement.
When Arthur is firing his assault rifle at the invading mooks, Eames pushes him aside, tells him "You mustn't be afraid to dream a little bigger, darling.", and pulls out a revolver-action grenade launcher and blows them all away.
Arthur managing to provide the kick at dream stage 2, despite having less time than he thought and no gravity.
Ariadne going up a level (no, not a dream level) and deciding to take care of Mal herself.
When they cut back to her, she has this awesome look on her face that said, "Sorry, love ya, Cobb, but I've had enough of your bullshit. Time to get things done."
Cobb:[aghast] What are you doing?! Ariadne:Improvising!
Eames pulling a One-Man Army in the snow fortress.
Yusuf's driving, which somehow gets the crew through the City.
As well as him defending himself and the others from Fischer's security with a pistol.
And flipping off Fischer's security just before he drives over the edge.
Saito taking out some of the invading soldiers with a grenade, despite literally being seconds away from death.
Ariadne's first journey into a dream, where she takes the road and flips half of it upside down, over their heads!
Keep in mind: she has only just found out that she can manipulate the dreamworld, and her first idea is to turn half the city upside down. Girl dreams big.
In "The Cobol Job," Arthur holds up a jewelry store and makes a suicidal charge against a bunch of cops to buy time for Cobb.
A severely understated one near the end: Saito has just died and spent 50~60 years in Limbo. First thing he does when he wakes up? Honor his promise to Cobb.
Saito's line:
Arthur: "You'd have to buy out the entire first class cabin, including the flight attendant!" Saito: "I bought the airline." (cue stunned looks from the crew) Saito: "It... seemed neater."
When all four kicks come through: Ariadne falls off the building, then is woken up to the exploding base, which sends her to the crashing elevator, then to the truck falling down into the river, and finally back to reality (or what passes as it in this film).
A small one that most don't know: they actually dropped Elliot Page nearly 30 feet at a green-screen stage to get the shot of Ariadne leaving Limbo, when they could've just CG'd the sensation of him falling while filming them prone.
Saito's ability to actually survive Limbo with his mind intact.
Fischer's utterly apathetic and deadpan reaction to being kidnapped is as awesome as it is hilarious.
"I'm insured for kidnapping for up to ten million, so this should be simple."
Not particularly smart to show his hand like that.
