I guess I was going pretty hard out...
I overheated one of the hydraulics on my stepper/stairclimber last night. It just lost all pressure, but was fine once I'd given it a chance to cool down. Ooops. Of course, it did only cost me about $80 from Kmart...um....7 years ago, I think. Of course, it's only really been used intermittently until this year.