Play The Independent Games Festival
The Seventh Annual Independent Games Festival doesn't start until tomorrow (indeed, the kiosks at the Moscone Center aren't even set up yet), but if you're interested in the contenders you can play many of them at Gamespot. While not all of the games have demos, the ones that do are definitely worth checking out.
Some really great independent games are made because a lot of times the programmers are more worried about making a sweet game than making money. It's festivals like these that give these games what they deserve: recognition. Kudos to the people that run it.