Quite simple - You post the name of a PD member. The next person posts what they think will beat that member, then posts the name of the next member.
It would go something like this:
God pwned (A annoying member) with his Admin powers. Next member: Peeki
Peeki got pwned by getting stripped of his moderator powers. Next member: Dash
Dash got pwned with Ritalin. Next member:
Game starts in next post!