Well, I used to play Mafia Wars, Farmville, Fishville, Cityville and Cafe World.
My most favorite was Farmville and Cafeworld.
Well, everything is past..!! I left them about June '10 or so. Got really addicted and always try to come online at time otherwise my crops would have died or the food would have burnt.
So one day I sold everything I created and then blocked all the games..!!