Knuckle Cracking Toy

I found this really cool toy that makes the noise of cracking your knuckle. It's called the Yubi-Poki virtual knuckle cracker. It's advertised as a great thing to use after you've used up all of your fingures cracks so that you can keep on enjoying knuckle cracking. (http://inventorspot.com/articles/yubipoki_virtual_dual_purpose_knuckle_cracker_toy_28215).