Have a spare XR50/pit bike engine and parts lying around and an old mountain bike collecting cobwebs in your garage? Spend your weekend turning them into a fun, efficient way of getting around town with a Motoped ($1,000) conversion kit. All you need to bring to the project are a Honda 50-190cc motor, gas tank, seat, and a couple other parts, along with forks, brakes, wheels, tires, cranks, and pedals from a mountain bike. The kit comes with everything else: frame, swing arm, jack shaft, bottom bracket, rear hub, sprockets, and exhaust. When you're finished, you'll have a 4-stroke motorized bike that you can pedal, or ride on- and off-road.