Tomorrow for my game I want to run a chase scene. The characters are heading across the desert on Sand Skiffs (from Sandstorm), and I want to do an encounter where they find themselves being pursued and attacked by guys riding Ashworms. Kind of like the guys from the next car on the freeway trying to kill you.
Anyone have any suggestions on how to run this kind of encounter? Variables to use, checks to make, mechanics for various actions?