Ooh, conspiracy theories, fun!!!
My daddy's a 70-year-old conspiracy theorist. Here are my top two all-time favorites (not necessarily in any sort of favorite order)
1. The government is out to get him because they caught him speeding. They are planning on taking over the world, and in order to do that they must impoverish the working man by catching him speeding, fining him, and making him think he might get out of it by spending *more* money on a lawyer.
2. President Bush is a Nazi. Because "Bush" can be pronounced the same by spelling it "Busch," which is a German name, and because Bush is so obviously German (because of his name) he *MUST* have been descended from Hitler (??) and so he's a Nazi. The really funny thing? Dad's a 3rd generation German.
I've learned to smile and nod while I'm with him, and allow myself to laugh when I'm not around him. Other than his incredible conspiracy theories, he's actually a fairly normal guy. Well, no, he's not. Never mind. I'm surprised he hasn't thought of Mark's traffic theory, although most of Dad's theories revolve around SOMEONE trying to take over the world. Which is definitely what the president would do if he was a Nazi.
I could tell you more family conspiracy stories, but I don't want to further hijack the OP.