Anybody play the indie games on Xbox Live Marketplace? Here are a few of my favorites you should definitly check out:

1. BloodyCheckers: Great RPG, checkers is addictive and easy to pick up and play. With a 30 hours story you can't go wrong

2. Avatar Golf: Course Editor, 8 person online play, all around great game

3. Puzzle games like Vizati, Blocks that matter, Hack this game, etc.

I think BloodyCheckers and Avatar Golf should be arcade games. They are that good and deserve a higher price tag.