Here's something that's guaranteed to crack up your friends--a knuckle-cracking simulator that ensures you never run out of knuckles to crack.
The idea, according to Strapya World, which sells the product, is looking tough--since "you always see fighters cracking their knuckles before they start fighting, right?"
I'm just surprised Japan's quirky toymaker Bandai didn't think this one up before Strapya World. Though at a piddling 500 yen ($5.26), don't expect this gimmick to be crackingly loud (it sounds tinny in the vid below) or to last past a few good abusive cracks.
The Yubi-Poki virtual knuckle cracker comes in three colors, each with its own (annoying) sound.