There are, of course, numerous science/fantasy/geek/nerd/etc. boards other than this one, but yet it seems as if everyone on all of these boards and chat rooms can make certain references that everyone picks up on without further explanation.
For instance, "Brain the size of a planet" needs no explanation.
Does anyone wish to add to this list?
Monty Python's various works
Hitchhiker's Guide to the Galaxy in all of its variations