Today I was wearing my "there's no place like 127.0.0.1" shirt, and thus found myself explaining as much of how the Internet is put together as will fit in an elevator ride in a tall office building. I explained to my inquirer that while he's used to referring to sites by names, computers also have numbers, like this, and that this particular number is very special: it refers to "this computer that I'm typing on right now". Oh, he said, like "home base". Ding.
At that moment the elevator arrived in the lobby, so we did not get into IPv6.