I just don't "get" the humor of the onion. It is just so on the nose that it looses all value. Like the "man makes a post on the internet" article that made the rounds that everyone loved so much. How is something like that funny? Other than perhaps appreciating on some kind of ironic level that a newspaper is reporting something mundane. But that is ruined as soon as you figure out that the onion is a humor paper. So basically you have to keep up the illusion that you're reading a real newspaper, and laugh at "why would they report this, that's so stupid". But when the entire joke is that a real paper wouldn't do something, and it's not a real paper.... Where is the humor?
Also, could somebody explain to me why "2 and a half men" is popular?
Ahh, that's it then. I never found MAD funny. Monty Python I love, but the only "spoof" I ever really found funny was a few by Weird Al. But really, that's mostly because of his lyrical genius, not because of the fact that it's a spoof.