Sun 10 Jun 2012
No, I don't mean like this, but rather, If you spent any time trying to figure out xkcd's Umwelt April Fool comic this year, you may be interested in the Haskell source code. They used all sorts of information about you, the browser you were using, the resolution of your screen, to the geocoding of the network address you came from, etc. to serve up a custom web comic.
Today, davean posted to github the code for waldo, the engine he wrote to drive that comic.
Alas, he was not kind enough to actually supply the code for the umwelt comic strip itself, so you'll still be left wondering if the internet managed to find all of the Easter eggs. (Are they still Easter eggs when you release something a week before Easter?) You may find the list of links below useful if you want to get a feel for the different responses it gave people.
[Update: Jun 10, 9:09pm] davean just posted a rather insightful post mortem of the development of waldo that talks a bit about why xkcd uses Haskell internally.