Pogo.com is totally addictive but lots of fun.

It's not only a place to play games, but there are so many to choose from and you can play the single player games or you can play against someone. You can also chat with the people you are playing with or that are in your game room. I just learned how to play backgammon recently and the first time I played, the other player was very nice and gave me lots of pointers on how to play the game.