For those who don't know, tomorrow is the annual Villa Magica/MAMCO Xmas Party (MAMCO is the main art museum in Geneva). It takes place every year (it's the 8th one) and it's pretty much one of the best parties in Geneva. The crowd is always a good mix of locals and expats, and the atmosphere is always very nice. It's free and takes place from 8pm to 4am in the MAMCO complex (where the club La Sip is as well), drinks are cheap and it's definitely a great place to meet people.
People new to Geneva should definitely check it out.
There's more info here: http://www.facebook.com/event.php?eid=162398170469675
Cheers!