Saturday is Pi Day in the U.S.: 3/14/15. If you have access to a laser engraver, this would be a neat Pi Day craft:
A cork trivet with the pi up to the first thousand digits by Lenore M. Edman at Evil Mad Scientist. Happy Pi Day! Bonus points for pi activities done at 9:26 in the morning.
Note: I wasn’t paid or perked to mention this; just passing along a good thing.