For 800 MS Points you can download Peggle right now, and straight up you really should. Just stop reading and start downloading. This game provides hours of entertain and challenge that even some $60 games cannot provide.
When you first start up Peggle it looks fairly simple. You control only one thing during the entire game, a small gun located at the top of the screen that can pivot left and right to try and launch your peg and bounce it around to hit all of the orange pegs with varying degrees of obstacles and power ups. You only have 10 shots but can earn more by earning a certain amount of points in a shot or getting your peg into a moving bowl at the bottom.
Sounds simple but controlling a bounce to hit the last 2 orange pegs when you only have one left can be nerve racking, especially when you miss completely. The game adds a degree of fun with different characters that can give you different power ups, and extra ball falling, a fireball ball that rolls through all pegs, and so on.
Once you get past the Adventure mode which introduces you to all the Peggle powers and all the Peggle levels you then gain access to the challenge menu. With over 25 puzzles with different objectives, a Master Challenge mode, and online play you will find yourself playing Peggle when you should be doing...well...anything and everything else.
800 points, well rounded puzzle game, and it serves what I think puzzle games should serve on Xbox Live, a distraction, something to kill time. I play it listening to the Bombcast, waiting for demos to download, and talking on the phone with my girlfriend. Its a filler game that will fill more than you want. So why are you still reading? Go get addicted to Peggle already.