When I was a freshman, and an international student newly arrived in the United States, I learned to my astonishment that "breakfast cereal" means not Kellogg's corn flakes or Alpen Muesli - the only ones I had encountered before - but an entire isle of variously shaped and coloured offerings. My first grocery shopping trips where always whole-afternoon affairs.
I also found out about this game called football. Where feet are hardly used at all. Apart from that the rules were all mystifying to me: even the shape of the ball was something I'd never seen before, like a lemon gone wrong. Of course, there are plenty of other games with obtuse rules, such as cricket or snooker, and odd ways of keeping track of the score, such as in tennis or snooker, and creative and unusual orders of hitting the balls, such as in pool - or snooker.
My freshman year was the first year my dorm had gone co-ed. There were plenty of kind upperclassmen who were eager to explain the rules of football to a foreign newcomer. But I waved away the kind offers, and set out to divine the rules just from watching the games. It was a jumble. Here were these guys with shoulders like the Incredible Hulk's and legs like Rudolf Valentino's, huddling, bending, throwing the ball in the wrong direction, and then all running around in incomprehensible patterns that made my friends shout an appreciative "Yeah!" I remained throroughly mystified.
[The Obamas' dog probably has a better idea of why he's running than I did about the rules of football.]
But one day I wandered outside, into a pickup game of touch football. My friends invited me in, on the principle of learning by doing. It was kind of them: really, I had no clue what was going on.