RigidBody that does nothing but OnCollisionEnter

I need a way to set up a rigidbody so that it doesnt effect the game object but still allows for oncollisionenter. Any idea how to do this?

ex normally when I put one on, my game object flips and spins around.

u probably need a trigger instead of collider. http://unity3d.com/support/documentation/ScriptReference/Collider.OnTriggerEnter.html
on collider check is trigger

Are you adding a Rigidbody to a CharacterController? That’s not a good idea - the character gets crazy! To check CharacterController collisions, you must use OnControllerColliderHit in the character script.

But if you are moving a rigidbody and don’t want it to start spinning when colliding to something, set rigidbody.freezeRotation = true.