Go to sleep.

I have a rigidbody with a box collider that drops onto a (flat) terrain with a terrain collider. Gravity is normal to the plane. The rigidbody slowly skates around and doesn't go to sleep. I tried programatically setting the rigidbody's sleep velocities to 100... still jiggling around. I could make the rigidbody kinematic, but (a) I shouldn't have to; (b) I'd have to figure out when it is flat on the terrain, and I can't check that (easily) if it doesn't go to sleep.

Thanks in advance.