Sega Swirl is easy to pick up and play, girls love it too.
Virtua Tennis and Amplitude. Both fun on their own but easy and a ton of fun to turn into drinking games. I find Amplitude a tough sell because 90% of people don't know what the fuck is going on and won't take the time to learn it. Also, 10% of those people are so bad at grasping the concept/have no rythm that they simply can't play it no matter how many times you tell them how to play. But for those that know how to play and want to step it up, it's a great drinking game that even people that sit and watch can play along.
