It appears that through their Social Bicycling program, JUMP bikes offer a $1 credit to people who lock a bike to a charging hub, rather than just a ‘dumb’ bike rack or pole. JUMP claims that bicycles typically require a charge every 48 hours. I’d assume it’ll work the same way with Uber Bike.
Keeping the conservation of energy in mind, any other method of charging isn’t feasible.
Runtastic Push-Ups on iOS counts pushups either with touch input (nose touches screen) or the proximity sensor (you get close enough but your nose doesn’t quite hit the screen).