We've all heard of tree houses and pools in the backyard, but a backyard roller coaster? Why not, said Jon and Natasha Cain.

The couple built a 12-foot-high roller coaster in their backyard in 2009, and a video posted to Youtube in February has gone viral. The roller coaster, which took three weeks to build, is made of PVC tubing, concrete and treated lumber. The Cains originally thought the roller coaster would cost $300, but it ended up setting them back $700.

Still, judging by how much fun their son is having, that seems like a worthwhile investment.

"I was concerned at first," Natasha said of the roller coaster's safety. "But we test-rode it several times. And only my children are allowed on it."

-- Follow Robbie Levin on Twitter @RobbieLevin.

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