ThinkGeek, which sells "stuff for smart masses", often has a one-day special for April Fools Day. This year it's a supersecret anagram shirt, available free, today only, here when you buy $10 worth of other stuff.
The shirt reads "Fake Ghostlike Photons". With the help of the Internet Anagram Server, I believe I have figured out the message.
Hint: They're making fun of you!
Spoiler (i.e. the answer, ROT13 encoded): sbbyf fubc ng guvaxtrrx.