I noticed the Chuck Norris meme from College Humor. Photoshopped images of him kept showing up, often enough that I started to wonder what all the fuss was about. A quick google later, I found Mark Christian's chronicling of the meme's start. Chuck Norris has even mentioned the meme on his own site.
As for the underscores, I've switched all my underscore-containing del.icio.us tags to be CamelCase instead. ChuckNorris is more popular than Chuck_Norris ("Bob Dole, Bob Dole, Bob Dole, Bob D... zzz") on del.icio.us, you see. Apologies to my feed reader buddies; Blogger is dumb and always sends out even minor edits.