GM has partnered with car-sharing service RelayRides to launch a rental program in 2012. Owners of vehicles equipped with OnStar voluntarily join the program, and can rent out their vehicle at rates and availability they set. RelayRides' mobile app is expected to be nationally ready by the end of 2012. If you've got a pickup used only for weekend boat or RV pulling, with a good bedliner, this could produce income from people needing a truck to move, get a pile of bricks home, or keep contractors mobile while their trucks are in for service.