Abstract: The invention is a yo-yo in which at least one of the yo-yo's sides includes a user-adjustable clutch mechanism. The mechanism includes a cam and can be set by a user to cause the yo-yo, when it is spinning, to automatically return to a user's hand once the yo-yo's rotational velocity has decreased to a low level. A user can also set the mechanism to prevent the yo-yo from sleeping, or to enhance the yo-yo's ability to sleep at the end of the tether. A user-movable part of the clutch mechanism may be in the form of a knob or lever that extends from a side of the yo-yo.