Anytime Beck goes up against Tessler. Especially the end of the fight in the first episode.
The fight between Beck, Cutler, and Paige. Cutler throws his disc at Paige and misses her. She asks if he was even programmed for combat, but it turns out he hit the switch controlling the wind turbine she's standing next to. As Paige is being dragged away by her parachute catching the wind, Cutler quips, "Nope. Aerodynamics."
Zed enters a street race against some local thugs. Two of the racers begin working together to eliminate the other racers and they finally reach Zed... who activates the equivalent of a nitro boost and blows them away.
"Scars-Part 2" is basically a whole episode of Tron being awesome. From schooling Beck on the Lightcycles, to his epic throwdown with Dyson. Just goes to show, the old man's still got it.
Distilled down to the very essence of awesome with this exchange between two guards while Dyson is torturing a silent Tron:
The Phrase spoken by Beck and Guard 1, Cyrus, who rescues Tron in the end.
"We can't let the Revolution end before it really begins."
Tessler's "nightmare", in which the Renegade completely curb-stomps him. It may be Tessler's worst nightmare, but it's a dream come true for the people of Argon city, and it shows that the Renegade has proven himself to be a lot more than a simple Freedom Fighter.
Mara and crew successfully repairing all the tanks they were forced to repair. Pavel's defeated attitude is just the cherry on top.
Beck breaks out of a living-generator/torture-chair while it's boiling him alive by waiting for the heat to loosen the restraints. Then he fights off Cyrus and foils his Evil Plan.
Mara free-coding a Recognizer as it's bearing down on her, triggering a set of Disaster Dominoes to top it off.
Keller stopping Pavel and helping out Beck, using Pavel's own discarded staff. Beck claims that he had Pavel under control, which he indeed did, but Keller really wanted to hit him.
In "Rendezvous", Paige, finding her escape by light-cycle blocked by a tank, gets past it by turning off the bike, leaping over the tank, then reactivating the bike while passing over it so the light-wall is within the turning radius of the turret.