Homer Simpson would love Kevin's bowling ball that is engineered to be steered into the pins each time. Or is it?

Grant is sure of his advantage in a paintball bet if he's wearing night vision goggles he built out of materials rustled up in the garage.

The guys hit the range with a lot of duct tape, and a lot of scenarios to craft something to stop a 9mm Luger round.

In the first pool test of Kevin & Grant's homemade submarine, things start to go belly up when Grant smells smoke.

Kevin and Grant turn their first test - choosing a tire for the monocycle - into a project of its own. Giant tire bowling with trash can "pins."

The guys build their life size punching robots, complete with pneumatic power. Round one proves to be brutal.

The mission is to escape from the island using nothing more than what they would have had in the ‘50s. Grant is in a makeshift raft, Kevin is going to swim.

The guys have built dream motorcycle chariots, and as always they had different approaches for their builds. Let’s see what happens at the first test.

The guys each invest in some heavy junkers and modify them to stand up to their personal Mad Max demolition derby. Lots of spikes are used.

Kevin and Grant wire together a crazy homemade lie detector with spare parts in the garage. They’ve kicked it up a notch by adding a shock if they are caught in a lie.

Kevin shows how quicksand is created by agitating a sand and water mixture. With Grant standing in it as a test.

The guys test several "squirt gun" formats, with one powerful enough to knock down a brick wall. Once that's done, they're off to build a better version.

People jump off tall things. Grant and Kevin want to do it right, so part of the prep is to create a cushion. Their first test is with carboard boxes

Kevin and Grant watched the internet community jumping off things using small parachutes, umbrellas, and tarps to break their fall. Naturally, they tried it too.

Kevin and Grant build two different types of earthquake resistant test tables and their own seismograph. Initial tests in the back of Grant’s truck provided inspiration.

Fascinated the the aerodynamics and speed of hydrofoils, the guys decide to build one. They understand the science, but they’ve never done it before. Prototype testing reveals what to do next.

Kevin and Grant want to do lawnmower jousting right, from armor to weaponry. The first step is comprehensive tests for the best jousting pole.

After Grant and Kevin watch some three-wheeled destruction on the internet, they brainstorm how they could do it better - with motorized trikes.

The guys decide they can one up some epic cannon fails with their own homemade Gatling gun, customized to shoot meatballs. Check out the build of both meat and firepower.

After viewing typical science fair style homemade volcanoes, Kevin and Grant head into the field to build a giant version, complete with the three phases of volcanic explosion.

The guys are happy with their soapbox racer built to go off-road, but as always they want to test it before it goes into the field. They use Kevin’s street, curbs, and a bit of garden to start.

Kevin and Grant weld an air cannon in Kevin’s garage to break Don Meredith’s football passing record of 83 yards. They bring the cannon to the field for a "slug" test. Is it record worthy?

What is a James Bond test? Trying to stop a car going 30mph with no brakes, but lots of gadgets. Parachutes, air flaps and more are deployed.

What could be better than having a beer delivered straight from the fridge to the garage? Kevin and Grant build a pneumatic tube system and start testing.

The guys are serious about building a giant paper airplane that will fly 200 yards. Let the testing begin.

Kevin and Grant are building a vortex cannon to see how many trash cans they can topple. Attempt #1 includes propane and air.

Kevin shows Grant how quantum levitation works with magnets and superconductive material. They play with the materials before creating their visionary slot car toy.

The guys don't just build a mini-golf course, they build one that guarantees a hole in one every single time.

They’ve tested the drone with paintball ammo. Now we watch as Grant and Kevin make the first person headsets and add smoke countermeasures.

Kevin and Grant watch some mini-golf and get the idea to build their own course and try to sink repeated holes-in-one. Of course they make the course as hard as possible.

Grant and Kevin have tested a basic golf cart. They now systematically strip the cart for their plan to make it bigger and tougher.

The guys want to be superheroes. They build a wall walking machine with vacuum cleaners and now face a 50 ft. wall.