EPIPHANIES are rarer in life than in literature. But they do occur, those moments when everything changes in an instant, when you know your understanding of the world will never be quite the same. I had one of those this summer, when I saw my first potato cannon. We were in Maine, visiting friends who live in a rural area up the coast. It was early evening, cocktail hour, and we were sitting on the back porch watching the kids play in the grass. "Hey," said my friend, "want to shoot the potato cannon?" Minutes later he emerged from the barn with the thing in hand: four feet of white plastic PVC plumbing pipe, capped at one end. On the underside was a red button, an igniter taken from a gas barbecue. Using a ramrod, he forced a baking potato down the barrel. Then he unscrewed the back of the pipe, sprayed a shot of Aquanet hairspray into the combustion chamber, and closed it back up. He handed it to me. I pressed the button. As it turns out, Aquanet (like Right Guard underarm deodorant, and a number of other grooming products) is made with propane. Compressed and ignited, propane explodes. Like a 10. gauge shotgun. Flames leapt from the muzzle. The potato flew about half a mile before I lost sight of it. The report was tremendous. The dogs hid. I was in love. "That's nothing," said my friend. "Wait till it gets dark. We'll cut open a lightstick and pour it on the potato. It's like a tracer round." Obviously I needed a potato cannon. It wasn't difficult to find. The Internet is home to a thriving potato cannon community. Overall, it's a group with creative instincts, subversive tendencies, and the free time to combine them. If it explodes and you can imagine it, you can find it online, often with blueprints. Within 15 minutes, I came across spud pistols, propane-propelled tennis ball guns, vegetable mortars with car battery igniters, as well as actual potato cannons, with wheels. I liked the fan pages best. On Spudgun.com, a guy named Dave Malis posted a photograph of himself "shooting toilet paper soaked in Coleman lantern fuel." Just down the page, Nathan Lovern, no hometown listed, is pictured in his undershorts cradling a PVC bazooka the size of a telephone pole. "Well I've completed the Big One," he writes. "It KICKS like a mule!!!!!! It knocked me back about a foot. I used about 15 seconds of White Rain hairspray and shot a plastic bottle full of powdered Kool Aid. It went about 300 yards and hit a tree and exploded!!!!! It was awesome!!!!!! I've got to come up with some cheap ammo." After a bit more searching I wound up at Spudtech.com, official site of the Spudgun Technology Center. Spudtech is the Bell Labs of the potato cannon industry. A few years ago, its engineers created the SP9004, a remarkable device, billed (no doubt accurately) as "the world's most advanced hand held laser-guided bolt-action aluminum potato rifle." Tempting. In the end I settled for a conventional plastic model with a rifled barrel. Spudtech shipped it to my house in a week for under a hundred bucks, no permit necessary. In 1998, the Bureau of Alcohol, Tobacco and Firearms released its official position on potato cannons. Spudguns don't qualify as "firearms," the ATF said, "provided that they are used solely for launching potatoes for recreational purposes." As long as it's a hobby, the feds are fine with it. (Go pro, and there's paperwork to fill out.) Apparently my neighbors feel the same way. They haven't complained yet. And they've had plenty of opportunities. What happens if you fire a lime pointblank at a stockade fence? We now know. What about an apple? How about marshmallows? All experiments we've conducted in my backyard. (For the record, potatoes remain the most effective projectile food. Apples are too mushy. Marshmallows tend to melt in the barrel and clog the rifling.) A couple of Sundays ago, my kids and I decided to test our marksmanship. We made a bipod out of two-by-fours to steady our aim, and painted a target on a stump. The first one to hit the center with a potato got ice cream. I'm embarrassed to say, I didn't do well. My first shot missed entirely. So did my son's. (I hit a tree, he knocked a hole in the fence.) Both of the girls did better, but it was our youngest, the 2-year-old, who prevailed. She hit the bull's-eye dead on. The center of the stump disintegrated. She was thrilled, and so were we. In the end, we all got ice cream. -Tucker Carlson