Of course... there is Pi Day, but that's not really the geekiest day of them all. Today is actually geekier. It's 42-day!!! So be good to your inner-geek (or outer geek for that matter). And don't forget your towel!
If you didn't get it yet... well I have to break it to you. You're not geeky enough for 42-day. But I'll explain: the date today is 10-10-10. Binary 101010 is 42 in decimal... 42 has meaning for everyone (mostly geeks) that has read The Hitchhikers guide to the Galaxy.
To celebrate this 42-day here are some links to feed your inner-geek:
Update 10-10-10: Turns out there is already a whole site dedicated to the geekiest day of this century.