Give a man a fish and feed him for a day....Teach him to use the internet and he won't bother you for weeks!
We've all been suckered into them; sometimes willing and sometimes not. But they all seem to get stuck in our heads and in our collective consciousness. These "memes" (NOT to be confused with my stalkerish obsession) spread quickly and soon embed themselves into the mainstream. In the event you missed any, or just want to relive some, a great interactive timeline at Internet Memes (VIA Gawker) allows you to do so.