Peggle is the dumbest game to ever absorb every free ten minutes I have. But it's a PopCap game so of course it's addictive.
Speaking of stupid fun games. Some Indie games for Xbox Arcade. Extreme BabyMaking was pretty fun. For like five minutes. check out the demo it's rad if you're into over-the-top, "no fucking way someone made this game"... games. I mean you can give birth to your avatar and that's a new level of creepy all by itself.
Impossible Avatar escape was kinda neat to. When the difficultly levels span from "Impossible" to "Fucking shit fuck" that means something. Once again stick to demo only.