Controller Collider is Called Constantly

Check for or prevent collisions with the ground.

You can prevent controller collider collisions with the ground entirely by not moving down with Move or by using Move in stead of SimpleMove. Moving down with Transform.position or other methods will not trigger OnControllerColliderHit.

You can check for collisions with the ground using the ControllerColliderHit:

//by tag
function OnControllerColliderHit (hit : ControllerColliderHit) {
    if(hit.gameObject.tag != "ground") {
        //Do stuff
    }
}

or

//by position
function OnControllerColliderHit (hit : ControllerColliderHit) {
    if(hit.point.y > tooLow) {
        //Do stuff
    }
}

or

//by normal
function OnControllerColliderHit (hit : ControllerColliderHit) {
    if(Vector3.Angle(hit.gameObject.normal, transform.up) > threshold) {
        //Do stuff
    }
}

etc. There are any number of ways to check against ground collisions. The best depends on your setup.