Very Simple Avatar Controller

    public float movementSpeed = 0.1f;
    public float jumpSpeed = 10.0f;
    private bool isJumping = false;
    private bool isFalling = false;

    // Get Input and Move player
    void getInput()
    {
        float moveX = Input.GetAxis ("Horizontal") * movementSpeed;
        float moveZ = Input.GetAxis ("Vertical") * movementSpeed;

        transform.Translate(moveX, 0, moveZ);

        if ((Input.GetButtonDown("Jump")) && (isJumping == false) && (isFalling == false))
        {
            rigidbody.velocity = new Vector3(0,jumpSpeed,0);
            isJumping = true;
        }

        if ((rigidbody.velocity.y < -0.1f) && isJumping)
        {
            isJumping = false;
            isFalling = true;
        }

        if ((Mathf.Abs(rigidbody.velocity.y) < 0.1f) && isFalling )
        {
            isFalling = false;
        }
    }