Multiplayer turn-by-turn games?

[ssllogic]

I've been playing a lot of Wordfeud lately and I love it. The game itself is great but I really like the fact that my opponent and I can just make a turn whenever we like and don't have to be on at the same time.

Can anyone suggest any other multiplayer turn based games? I really don't care what the theme/genre is as the people I play with would play essentially anything. I'm really just interested in exploring more games with this mechanism.