1. (American) Failure of a device, usually in a non-repairable manner.
2. (British) Exclamation of surprised.
2. "The boss is back from vacation early!" "Shit the bed."
2. verb. To become mechanically inoperable beyond the point of repair. See also, fucked, fubar.
entymology and usage: "shit the bed" comes from the unfortunate final humiliation when an animal's (yes, including human's) bowels completely relax at the point of death, causing the contents of the colon to be expelled. To use the term as a "euphamism" for biological death is considered to be in poor taste. It is more often colorfully used in definition 2.
2. I was hoping that my car could be repaired, but the mechanic told me that it had shit the bed so I had it scrapped.
Mike: "What did you do?"
Jeff: "Fell down the stairs while my family was watching TV"
Mike: "That's not bad, at least you didn't shit the pool"