I am getting ready for a stint behind the GM's screen running two diffrent games. The first being PARANOIA. A classic roleplaying game with a rich 25 year history. It encourges the GM to plays with the PCs, as a cat toys does with a mouse.
My players have little experance with the setting but are have been playing with each other for a great long time. My first goal is to drive them apart, make them distrust and then elimate each other. I will provide the illusion of some control over their fates by letting them create their PCs.
My only issue is that one of the players is going to be very, very trigger happy and wants to take it out a certian player. Oh, the evil thoughts I have in the foiling of her.
After a session or two of Paranoia, I will switch to the next game.
Anyway, check out the new edition of Paranoia. It's due out in a few weeks and the link is on the side of the page here.