What's the problem with the Mars Spirit Rover? Too much info:
Spirit's science operations halted just as it crawled to the pointy rock and was about to begin drilling into it. The rover's computer rebooted itself more than 100 times over a two-day period and, at first, sent back beeps but no data. Engineers have since determined that the problem appears to involve too many files overloading the onboard computer memory.
Some days, I know exactly how it feels.