The thought of riding someone's homemade roller coaster kinda freaks me out (especially when the "car" looks like a car seat/lawnmower hybrid), but in just a year and half, John Ivers managed to build his own 180-foot long roller coaster right in his back yard. The "Blue Flash" even has it's own 360-degree loop, and if not for that part where everyone's neck snaps back (hello, whiplash), I'd be tempted to ride it. In the meantime, I'll stick with one of these. – Louis Ramirez

[via MAKE]