I GM almost ALL the time. It's funny. I ran a game with my regular weekend group for a long time, but I got really burnt out writing adventures and just kind of disenfranchised with the whole referee thing. So I decided to play and have everyone else GM. It went really badly, just not fun games, and I was forced back into my role as GM. I'm feeling good about it again, after seeing what happened with the other games. I also play in 2 other groups, but as for the main one, I'm just the GM all the time, as ruled by the group.