Who needs brakes? When you're converting a junk-stuffed shopping cart into an electric joy-ride-mobile, they're the last thing you worry about. MIT undergrad Charles Guan's LOLriokart—the name is a mash-up of Web and videogame-speak—grew out of his membership in the MIT Electronics Society, a student engineering club. With no plans to build a vehicle, he looked around the club's shop and spotted the shopping cart, some discarded wheels and an electric engine normally used in high-performance golf carts. He cut off the shopping cart's wheels, stripped out the basket underneath, and designed mounting plates for the motor, batteries and electronics.