I've had good luck running a hose from my Jeep's exhaust pipe. Dixie Gun Works makes a .32 caliber "mouse trap" that isn't as reliable but is more fun. Its a little brass muzzle loader that has a sort of a spoon shaped lever that sticks out over the muzzle. That's the trigger. You load it up with a few grains of Pyrodex and a pinch of birdshot and place it in the tunnel. When the critter tries to shove the spoon out of the way, it blows his head clean off. The difficult part using it for moles and such is getting it facing the right way so he comes at it from the front.
