Yes, here are my fave Live Arcade titles:
Uno is a good one - but only one player at a time, I think. Would be hard to do 2 players at the same console, as you can imagine.
Zuma is also great fun. 1 player too.
Tony - ya gotta get Geometry Wars, but more for you, not the g-friend.
Robotron - I love the original so much, I had to get this.
For non-live arcade:
Table Tennis - cheap and really fun
Gears Of War - had to include it, even though you already have it.
COD3 - you already have COD2 --- COD3 is a worthwhile upgrade. Sell COD2 on eBay. I think I got $27 for it...
I sent you a friend request. Let's play something together when we see each other on line.
- Jon