Jam Live is probably best described as a sandbox music game. It allows players to mess around with tracks and play with different elements of songs. It's also compatible with all those old guitar controllers you've got laying around too- bonus!
Kinect actually has some pretty cool games hanging around the Live servers you know? Definitely better than a lot of the retail boxed games that are out there at any rate. (cough*cough*StarWars*cough) This week, you can get 50% off of a bunch of them including Fruit Ninja and Double Fine Happy Action Theater.
And I'd be remiss if I didn't mention that Dragon's Lair is now on Xbox Live. Non-issue that it is, it's a classic and now I think it's on every home console ever. Almost. It may not be on the Atari 5200- I'm not sure about that one.
Big stuff on demand this week too- big as in Skyrim, Saint's Row the Third, and We Cheer! Game of the year candidate right there.