Mad Scientists

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.