One of the things I miss about playing games in stores with mixed groups of people who come and go is that you'd learn the most interesting things about...well, everything.
Even with a stable group and playing games you'll pick up weird tricks, weird bits, and other little factoids.
So, what have you learned around the table? And has it been useful or not?
Some of my favorites have been more interesting than useful. I learned about Japanese not having a proper future tense or much in the way of plural while playing L5R. Also about the various levels of politeness in the language.
Come to think of it, I've learned about as much about linguistics around the gaming table as I did from college courses.
Beyond that is other fun stuff. Bits of lore about weapons, types of armor, traditions of warrior communities and types of soldiers. Bits about fighting styles. Bits about ways castles work. A whole slew of historical stuff - including that 'historical' is normally the wrong word when talking about games.
And then there's the weird stuff. Like that the human body is fully functional for some time after death, things cannibals have said about the taste of human bodies, and some truly horrific ways people have died.
Again though, what about you?