imageThe idea: A network of people around the world who want to hang out with and host travelers -- for free.

Whose idea: Tripping

Why it's brilliant: Traveling is more fun when you have a free bed and someone to show you around. CEO Jen O'Neal once hosted a wealthy investor from Dallas -- "Totally not the kind of guy you'd expect to sleep on a couch... but he wanted to meet local people."

To make sure everyone stays safe, Tripping uses a thorough system of references and ratings.