GetAround is a basic idea -- most of our cars aren't in use during the day. We use them to drive to work, and then they just sit there until the work day is over.
What if someone else could be using them when we don't need them? GetAround provides you with a keyless entry system for your car. You can then register it on their site so that someone who needs wheels nearby can find it, and rent it from you. It's sort of like a hybrid of Rentalic and ZipCar.