This game is by far the best game out there to get together with some friends when you're in the mood to Rock Out.
Rock Band allows you to play the Guitar, Drums, or even the Vocals. The Guitar is very similar to Guitar Hero, actually it's the same thing, so if you've played that game before than the guitar parts should be no problem for you. As far as the drums go, they are rather difficult to get a handle on. In fact, I'm still trying out most songs on easy and still having a tough time on them. I really love the idea though, and anyone with just a little bit of school could easily become a beast with a little practice. Same goes with the vocals. On easy mode it's a breeze, but with increased difficulty settings, you need to learn how to change your pitch to match with the song.
All in all, Rock Band blows Guitar Hero out of the water thanks to the addition of 2 new band roles you can play as. There is even a large amount of customizable clothing options you can choose from, and you can make a character instead of having to choose from a pre set list. Also, with all of the Downloadable Content and extensive song list already included in the game itself, there is something out there for everybody.