A man dressed in a small, figure hugging dress and, hopefully, a monkey hat who was employed to start the skanking and/or moshing at expectations:low's early gigs.
Although the term originated here(in this particular useage), it is now used for many dancers employed by ska bands.

Space Monkey is a game that teens play where a person either chokes his/herself or has someone else do it until they almost pass out. It can cause brain damage due to lack of oxygen to the brain.

Consider the first monkeys shot into space. Without pain, without sacrifice, we are nothing.

A song by Placebo, track 4 on the album "Meds."

A game played by boys and girls ages 10-20 who can't manage to get their hands on any weed. Choking yourself causes lack of oxygen to the brain and can cause oneself to lose consciousness or die. Kids think that it makes them feel high, while really it just destroy's their brain.

A song by John Prine.

A term of endearment for someone from (or having returned from) Space. Usually followed by physical contact such as a tousling of the hair or other more intimate contact, depending on circumstances.
~Source: Richard Dean Anderson