Adding a tail to a rock-crawling machine that is built to move like a lizard.
A backyard thrill ride that propels riders down 180 feet of monorail at dizzying speeds.
A portable version of a counterweighted teeter-totter allows for a 90-degree jump, straight up.
Building a multipurpose lawn tool out of a home-made turbo jet.
Transforming a gyroplane into a gyroboat.
Souped-up wheelchairs that can go off-roading and have water cannons.
Creating a motorcycle that is powered by springs from a garage door.
A robotics genius attempts to build a robot that can beat him in a game of basketball.
An attempt to build a rocket belt strong enough to lift a man out of the water.
John and a computer engineer build hovercrafts from old lawn mowers.
Transforming an airplane into a machine that runs on electricity.
John challenges an inventor to add a sidecar to his homemade jet-powered motorbike.