I'm trying to "understand" what "knock, knock, who's there" jokes are all about, and I just don't get it. I've googled it, but all I understand so far is the typical (albeit apparently not necessary) structure:
Person A: Knock, knock.
Person B: Who's there?
Person A: [first name]
Person B: [same first name] who?
Person A: [same first name]-who ...
My working hypothesis :) - person A "knocks" at the door, is asked for his name, replies a first name, is asked for his last name... and then there seems to be a pun. The one and only knock, knock-joke I have potentially "understood" is
Person A: (...) Abie
Person B: Abie who?
Person A: Abie, C, D, E, F,... (not that I'd know what the alphabet has to do with knocking, but I guess that's asking too much)
Are these jokes just about a random recycling of the "[first name] who" sounds? What on Earth is funny about jokes like these:http://www.brownielocks.com/knockknock.html
Thanks a lot.