Hmmm, the only two I have are "Animal Crossing" and "Race Driver: Create and Race", which I just got yesterday and is hella hard. But there's a ton of them out now:

I've heard great things about Clubhouse Games, which is just a bunch of board & card games you can play online with people or by yourself. The good thing about those games is that you can just play for 5 or 10 minutes at a time and not have to commit too much time that you don't have :).