Computer jokes thread (link from this post from Chris Sell's blog). And there are some more here. Like Chris, I particularly liked this one.

Two strings walk into a bar. The first one says, "Bartender! Bartender! I want a drink!" The second one says, "Bartender! Bartender! I want a drink too! blaaaaaaaaah Eeeeeeeek yaaaaaaak oooooooh." The first one says, "Please excuse my friend. He isn't null terminated."