Today is 1/11/11

Calendar anomalies 

Today is 1/11/11

Some people keep an eye on their calendars for more than just Thanksgiving and Christmas. For them, dates are just as important for their numbers as for any event or commemoration.

For instance, math lovers can rejoice in the fact that there are unofficial holidays celebrating pi, square roots and even special nods to palindromes. And you don't have to be a mathematician to appreciate a nifty occurrence like this.
In honor of today, we look back at other dates that have caused figure frenzies.