So someone comes up to you and says the Apollo missions were faked, the Face on Mars is real, aliens eat cow rectums (recta?), Nibiru will kill us in 2012, and NASA is covering it all up.
What do you do?
You say "I want to see the evidence!"
But it's terribly important to look critical when you say it. Just saying something won't do it; you have to use facial expressions in a way to convey your utter disbelief. Say, like this one:
Or, if they've sent all this garbage via email, just send 'em that picture. It should express your feelings pretty well.
And if that doesn't work, try this one:
If that one doesn't work, they're hopeless. Let them buy all the lottery tickets and homepathic remedies they want. They're beyond help.
Tip o' the lens cap to Andy Ihnatko for taking those pictures.