Biking is all well and good, but unless you only eat baguettes it's tough to ride one to the grocery store, not to mention toting the kids to soccer practice on one. However, nothing really beats moving at a quick clip with the wind blowing through your hair, pedaling your heart out. Enter the HumanCar Quadcycle. Kind of a modern update to Fred Flintstone's car, the Quadcycle is a bike bred with a compact car. It seats four, and the two people up front pedal and steer. If you're worried about getting up hills, it comes with an electric motor to give you a boost when your legs feel like spaghetti. It's currently in the prototype phase and has been tested tooling around Seattle with great results. While no one is going to go out and replace their Civic with one of these, it looks like a blast and would be a great way to spend an afternoon with three friends. And while a price hasn't been announced for the Quadcycle, you can put a deposit down on it knowing it's guaranteed to be cheaper than the Tesla Roadster, albeit a touch slower. — Adam Frucci

Human Car, via Treehugger