What People Do on Friday Nights

I have a theory. That people who don't go out on Friday nights to do culturally-acceptable social things hide at home so that other people won't see them doing lame things.

I say this because last night instead of lesson planning, paper grading, or book writng, I went to the gym around 8pm. The place was DEAD. Weeknights around 8pm, you can't get a treadmill. Friday night? Totally empty.