A video of a three-year-old boy riding a backyard roller coaster built by what he no doubt thinks are the coolest parents ever has been making the rounds online.

The video--uploaded to YouTube in February--shows the boy whipping around the makeshift roller coaster as his father, Jon Cain, looks on.

The Lancaster, Ohio, couple, who own a local car dealership, built the roller coaster in 2009 on a whim, the boy's mother, Natasha Cain, told Yahoo News.

"We thought, 'Why not? Let's make one,'" Cain said.

The 12-foot-high roller coaster--made of PVC tubing and concrete--took three weeks to build and cost $700, Cain said. "We thought it would cost about $300," she said. "But you can't have a half-built roller coaster."

She added that they cleared the coaster-construction plan with the city's board first. "They said, 'Go ahead, build it,'" Cain said.

But is it safe?

"I was concerned at first," Cain said. "But we test-rode it several times. And only my children are allowed on it."

The roller coaster is still standing, though the Cains are planning to dismantle it in order to sell their home.

Backyard roller coasters are not terribly uncommon, at least in the United States.

In 2010, Popular Mechanics gave an Oklahoma City man its coveted Backyard Genius award for his DIY roller coaster. His, though, sounds a little more elaborate than the Cains' creation:

On a 10-acre plot southwest of Oklahoma City, Jeremy Reid built an unexpected addition to his parents' backyard: a roller coaster. "I thought it would be great to have a small one to piece together and ride," he says. "Once I started taking college engineering courses, I realized I could probably design and build one on my own." And so began a monumental project that included 2900 board feet of southern yellow pine and 7000 assorted screws and nails. For the next four years, Reid conjured up ways to raise dozens of supports for the hills, laminate the track and piece it all together. Riders—limited to close friends and family because of liability concerns—sit in a single-seat cart built from an abandoned stadium seat, which is winched up the first hill by a 1-hp electric motor. A 16-foot drop propels the car to 18 mph; the rider then zips over another hill, down the sloping backyard and around a 50-degree bank that pulls 2 g's. Nearly 1 minute and 450 feet after the initial drop, the car returns to the lift. Reid estimates he spent $10,000 on the project.

EHow.com even offers a step-by-step guide to building them.