[xkcd](http://xkcd.com/), the great geek webcomic that I have [mentioned](http://michaelgalloy.com/2009/03/06/correlation-vs-causation.html) [before](http://michaelgalloy.com/2008/02/01/real-programmers.html), has a [printed book available for sale](http://store.xkcd.com/). Grab the [mousepad depicting the fight with red spiders from the book’s back cover](http://store.xkcd.com/xkcd/#Mousepad) while you’re there.