What's the Best Geek Joke You Know?

super_ogg writes "To break some of the office blues, I decided to tell the worst geek joke I know: 'Why did the Comp. Engineer get X-mas and Halloween mixed up? A: Because Oct(31) == Dec(25)!' Some groaned, some laughed, but only a geek could understand it. I was wondering what are some of the best/worst geek jokes people have out there for the Slashdot community?"