Hm... Hacking Baldur's Gate and becoming a dragon was pretty awesome. I suppose the same could be said for taking DOWN dragons later on

There was a fairly unfair glitch in the Shining Force games where casting a heal spell gauranteed you experience. Casting aura (a mass heal spell) gauranteed a lot of experience. I had a huge tolerance for monotony as a kid and would just bring in a healer or two into battle and just sit there and heal until their magic was gone and leave the battle and come back. And got one of my monks in SF2 so powerful she could take on the whole battle map alone. And took out the end boss in two hits. That was pethetically funny and awesome

Besting the rocket powered Metal Sonic in a speed match was pretty awesome. Showed him who's boss back when Sonic games were actually good. And Sonic CD is usually considered the best by anyone who's actually had a chance to play it :]