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Happy Pi Day

Today you can eat a slice of pizza, raise a toast with a piña colada, or just reflect for a moment on 3/14 at 1:59 p.m. to celebrate the most irrational holiday of the year: Pi Day. The observance commemorates the first few digits of one of the oldest known constants, 3.14159 ... and it also happens to coincide with Albert Einstein's birthday, which makes today a doubly cool day for science geeks. So what else can you do to celebrate?

You'll find plenty of online suggestions - including doing a pi-mile run (approximately equivalent to a 5K run), wearing a math-themed T-shirt, sending pi cards to your friends, screening the movie "Pi" on DVD, setting up some educational activities (which celebrate the fact that multiplying pi by the diameter of a circle gives you its circumference) ... or merely serving up some pie at a pi party.

If you're in the vicinity of San Francisco's Exploratorium museum, you can join in a ceremonial walk around the Pi Shrine and take part in other observances and experiments. Even if you're not anywhere near the real-life Exploratorium, you can participate virtually at the 'Splo museum in Second Life.

Whatever you do, don't be afraid to express your inner geek. If you've ever wanted to search for your phone number (or other number strings) among the millions of digits of pi, or play with the sounds and colors of pi, this is the day to do it.

One day a year really isn't enough to cover all the science geekery out there: Last month, we listed other science-themed holidays - and it looks as if the next excuse for a geekfest will be Yuri's Night, on April 12. Am I missing anything? Feel free to pass along your own scientific days to remember. In any case, hoist a piña colada (or at least a glass of pineapple juice) in the spirit of irrational exuberance.

P.S.: Whether or not you're a math geek, you'll enjoy this paean to pi from The Associated Press. And to mark Einstein's birthday, take a spin through our slide show tracing the great man's life.