I still can't believe this. I was on the Yankee Cannonball and both sets of brakes failed. The thing went around for about 5 times while they got a mechanic to fix it.
The best "breakdown" ever was when I was on a Roundup. It starts spinning, lifts up a little bit, goes back down, stops spinning, and the ride operator gets on, screams at this guy, forces him to exit, then starts the ride again. Now the guy must have apparently gotten back in line, because she turns around, yells at him instead, and forgets that the thing is still spinning. The best part is that this was the first ride of the day, and that the Cannonball broke.