Ace gets a few, most notably when he let every ounce of power he had loose on Googler in a rage after the villain sent Sparx back to the sixth dimension, resulting in a massive electrical build up... Which missed its intended target, but he sure as hell got points for trying.
Another good one for Ace is when he pulls a similar trick in Mark's school (while the observing fan club members cheering for him think that he's All Part of the Show). Ace creates a literal wall of electrical energy which terrified Fear out of the building, saving Ace from actually having to use this incredible build up to actually attack.
Sparx defeating Googler.
Sparx: Ha! That ones for me! Now we?re tied!
In fact, most of Sparx's fight scenes have an awesomeness to them. The series sometimes falls into Uncanny Valley with it's character movement and reactions, but Sparx is usually very fluid.
Chuck during an episode in which he obtained Temporary Superpowers and gave the resident Jerk Jock and bully, Wayne, the wedgie of a lifetime. He deserved it.
Lady Illusion when she takes Ace's place and dies for him during the final episode, which is as much a defiance of her programming as anything else.
Sam, explaining to Mark how she wouldn't be scared or disturbed if she ever saw aliens or anything out of the ordinary, but that she would feel better knowing that they weren't alone
Mark, taking on Googler's puppets with a piece of metal piping -and kicking both their non-existent behinds. It was mostly the expression on his face: surprisedly pleased with himself bordering on merciless (and for once playing up to the superhero stereotypes of melodrama).
Mark: Wanna join your friend?
Lord Fear tearing up the highway on the Doom Cycle (yes, it's a motorbike).
The first defeat of Lord Fear ironically gives HIM a crowning moment, who gives the typical "This isn't over, hero!" speech, accompanied by creepy, maniacal laughter, as he is fading away into Oblivion... Got to give the guy his kudos.
Ace casually lifts a truck off the guy who's repairing it underneath to ask for directions.
From the episode Search for Sparx. Ace gives up. Mark doesn't, and ends up taking on a giant killer wasp on his own, until Random turns good again and Ace pulls himself together.