Forget playing games for cash -- if you really want to raise the stakes, try losing your actual blood when you lose in the virtual world. That's the concept behind Blood Sport, a crowdfunded project that modifies game controllers to drain your body when your character takes damage. Their Arduino-based technology turns a gamepad's rumble signals (which often indicate that you've been hit) into commands for a blood collection machine. In theory, every digital punch or gunshot draws some of the red stuff from your arm. And before you ask: Blood Sport limits transfers based on your age, medical conditions and weight, so you won't pass out just because your gaming skills aren't up to snuff.