I definitely wasn't prepared for Alex's answer: tennis courts. The best part is that when I asked why, he said, "I used to make them." WHAT! I don't know if I ever would have known that about him if this topic had not come up. That's fascinating.
So now I'm into asking everybody I know; I have a feeling that different people's answers could be surprising or not necessarily expected. For example, this is mine:
Please leave a comment and let me know yours; I'm sure this will start a bunch of interesting conversations ^^