Sure, you use your muscles during a 12-hour Skyrim marathon and we're sure your phalanges are extremely trim, but that's not the same as using your muscles to play a game. Biomedical company Advancer Technologies has created the USB Biofeedback Game Controller, a device that reads the electromyographic output of unique muscles to move (in the above demo video) Mario through level one of Super Mario Bros. 3.
In the demo, this man's bulging right forearm controls the classic A button to jump, his right bicep moves Mario right, up and down, and his left bicep moves him left. Advancer sees applications for the USB Biofeedback Game Controller in treating patients with neuromuscular disease or injury, but we see it as a welcome break from those old-school, non-muscle-stimulating controls you've been using for so long. Don't ask how we know the type of controller you use -- we just know.
Advancer has provided instructions to build your own USB Biofeedback Game Controller, so there's really no excuse not to.