Uno is great game that will you keep you playing for hours.
First off, the multiplayer is great. You can play with up to four players either with people you know in real life or online. I suggest trying to get with 4 people because it's a lot more fun than playing with the computers.
Also, the rule customization is pretty neat too. You can play Uno anyway that you want. For example, you can set the amount of point needed to win to whatever number you want. There's also a lot more you can do than just that. It's really cool.
One bad thing about this game is that the music will probably start to annoy you at some point. The rule customization could also use a bit more options too. Other than that, this game is excellent. I recommend getting it if you own an Xbox 360. And besides, it's really cheap; only 400 Microsoft Points.
I give Uno an 8/10