With April Fool's Day coming at you tomorrow, expect erroneous publicist pitches, misleading tips, and phony Facebook friend requests. History is filled to the brim with elaborate tricks, from Discover magazine's April 1995 story on the naked ice borer to PC Computing's 1994 article on legislation aimed at banning Internet use while intoxicated. So how to sort out who's pulling the wool over your Lasik'd pair?

Slate's Jack Shafer is here to dole out the advice: Beware strange animals (scientists should wait till April 2 to announce new species discoveries); Turn off your radio (with such a linear medium, there's no lower third to tell you the DJ is telling a tale); Shun the British press (not that they won't like to you the other 364 days of the year); If they pranked before, they'll prank again (like men, dogs will always be dogs); and Too good to be true (just like we believe that weight loss supplement Alli to be).