If you were to bet $100 with somebody that you could beat them in a game, whether it be a higher score, winning rounds in a fighting game, VS mode on a puzzle game, racing, what would it be? I put this in the classics forum but it can apply to any console game, old and new.
One time somebody bet me $10 that they could beat the crap out of me at MK: Deadly Alliance for the PS2 back when it was a semi-new release. It just so happened that I was conquering that game and didn't believe me I could go through very hard mode with sub-zero without dying. Well I beat the kid without losing and got my $10 but I just ended up buying something off him that was $10 so I basically gave him the money back.
The only other game I may put money on is Kaboom! for Atari 2600 (with well working paddles).
I know there are probably millions of people who could kick our asses at our best games, but I know some of us are confident in our skills for certain games. Also it can't be just out of your group of friends or family, it would have to be a random person or somebody who you don't know how thier skills are on whatever game you'd choose. Also post if you have put money down on games and won.