In case you haven't bought the new You Don't Know Jack yet (and why haven't you, jerk, it's pretty damn cheap), there's now a two episode demo available for Xbox 360 (and coming soon for PS3).

Hell, even if you did buy the game, it's worth downloading because the two episodes included are completely different from any of the ones already included in the game. So, it's a bonus. Plus, downloads and good ratings help keep the demo visible online, and will hopefully help bump up sales.