MonoBehaviour.OnControllerColliderHit  

// this script pushes all rigidbodies that the character touches
var pushPower = 2.0;
function OnControllerColliderHit (hit : ControllerColliderHit)
{
var body : Rigidbody = hit.collider.attachedRigidbody;
// no rigidbody
if (body == null || body.isKinematic)
return;

// We dont want to push objects below us
if (hit.moveDirection.y < -0.3)
return;

// Calculate push direction from move direction,
// we only push objects to the sides never up and down
var pushDir = Vector3 (hit.moveDirection.x, 0, hit.moveDirection.z);

// If you know how fast your character is trying to move,
// then you can also multiply the push velocity by that.

// Apply the push
body.velocity = pushDir * pushPower;
}