Rule of Comedy: Know Thy Audience

The other day I was over at a friend's place watching Season 1 of Battlestar Galatica (the remake, not the original series).  He doesn't care about 24 so I'll have to catch up on that later.  Anyhow, it was the season finale of season 1 where the crew is wandering through space and they discover the planet Kobol.

I turned to my friend and said "Whew, it's a good thing they didn't land on the planet Fortran!"

He looked at me, not getting the reference.  "Fortran?" he said.  "What's Fortran?"

"Uh, never mind," I said.  "The joke wasn't very funny anyhow."