While not the most exciting game available through Xbox Live Arcade, Carcassonne is definitely good on a rainy day.

User Rating: 7.5 | Carcassonne X360
Carcassonne is a board game in which you maneuver pieces around to try and form castles, monasteries, roads, and farmlands. Gaining points for all you control, the singleplayer portion of the game is a good way to learn to play, but the real fun lies in playing online against real opponents. This is not a game I play real often, but it is good when you are bored and find yourself with nothing better to do. My only complaint is that the music does get old after awhile, and I usually just end up turning it off and putting on my own music.

I got this when it was free so that is an added bonus. In summary; if you're looking for a break from your other games you really can't go too wrong with Carcassonne. It's just a fun, simple board game which holds quite a bit of replay value in the multiplayer.