I was going to go with the "Moon Landing Conspiracy", but I can deal with conspiracy nut-cases by just ignoring them.
However, for some reason, I feel compelled to reply to educate everyone who sends me the email about "Mars looking bigger than the full Moon". It staggers me that I get these emails forwarded from people who are normally smart enough to know better - and in many cases, I have to remind them again that I already corrected them 2 years ago!
("Well, yes, I now know it was a hoax last time, but this time it comes from NASA!") 