I saw this on some random website today, so don’t trust me with the validity. But I am going with it:
Today was square root day. Apparently it only occurs 9 times per century. Today was 3/3/9 (3×3=9…yep, in 5th grade I was an awesome mathematician). The last one to occur was Feb. 2, 2004 – which happen to coincide with Groundhog day that year. The next one on schedule is April 4, 2016