You've been waiting for this, I know you have. So here's the first Rocket Bike with a 200-pound-thrust engine capable of blasting from 0 to 60 miles an hour in five seconds. Built by Tim Pickens, president of rocket-design firm Orion Propulsion, this power bike uses roofing tar instead of synthetic rubber fuel. A button on the handlebar fires the model-rocket motor inside the engine—which then sets off the larger motor by lighting the roof-tar fuel. Wowwee. Hope he had a helmet handy. Look for a pickup truck with removable 2,000-pound-thrust rocket strapped into the bed as Pickens's next pet...