If the mere existence of clothing for the children of computer geeks isn't enough to dispel the notion that at least somebody in the IT department's gettin' some, there are pictures. Not, thankfully, of Sysadmins Gone Wild, but of actual children wearing the stuff.
Most Kid's T-Shirts and Onesies Æ creepers at ThinkGeek have the scatalogical jokes you'd expect ("I TCP/IP, but mostly IP", "Input/Output") or declare your kid's allegiance to Linux or Perl. As if to demonstrate their interchangeability, the kids page includes a couple of dog shirts, too.
While you're at ThinkGeek, check out the Year of The Monkey gear for Chinese Zodiac-appropriate gifts. [thanks, Bill]