If, like Selena Gomez, you can't keep your hands to yourself, check out Yomaxer's version of metaphorical gin and juice, the Tri-Spinner Fidget Toy. Hands idle can kill time, and hands anxious may find some relief from the stress of living through it with this discreet board of spinning bearings.
Hold a Tri-Spinner by your disc of choice in one hand, and use the other to flick or whack one of its pointed ends to start the spinning. Yomaxer recommends using "small continuous strikes to keep it spinning indefinitely." With practice, you can also train your right or left hand to spin the toy on its own, perhaps growing skilled enough to put together and get ESPN to air a Fidget World Games, like they did the Rock-Paper-Scissors Tournament back in '07.
The Tri-Spinner fidgeter's friend weighs 2 ounces and measures around 1.8" in length per side.