Football: the goal line extends to infinity

I was watching football with Mr. Studmuffin on Sunday, and he explained to me that the goal line extends to infinity, meaning that if you are in bounds and cross the goal line, even if you go out of bounds--you still make a touch down! I never realized it before... but I guess that was why the player running the ball decided to do a somersault over an opponent. :) Okay, so is it super geeky of me to say that the favorite part of the explanation was the "infinity" part? Not just, "it goes on forever"... which you might have to further explain--what do you mean forever? Infinity is much easier to understand.