5. RickRoll'D:

The sad thing about the internet is that for so long, it lacked the equivalent of that thing where you point to a spot on someone's shirt and when they look down, you flick their nose. But thanks to the magic of YouTube and the power of Rick Astley's "Never Gonna Give You Up," that omission has been corrected. It's pretty simple: Just go on a discussion board and create a link that says something like "Lindsay Lohan Nipple Slip!" or "New Iron Man Trailer!" or even "Ivory-Billed Woodpecker Sighting!" (if you hang out with a bunch of ornithologists). But when they excitedly click through: Rick Astley! It's not side-splittingly hilarious; it's not knee-slappingly hilarious; it's more back-clickingly hilarious.