Pi Day
Here are some of the things I have done in the past:
Have a contest to see who can memorize the most numbers of pi
(To bring in other review skills) We graphed our favorite local pizza places. I called the top 3 and asked prices/sizes of all the cheese pizzas. Students had to then see which place had the best price per square inch for pizza (they then got to eat pizza)
With younger kids we had mothers bring in diffrent pies and recipies. We read the recipies, compaired ingrediants, graphed favorites, wrote thank you letters, etc. Wasn't much to do with 3.14 but the rest of the school was doing pi day so our 1st graders did too! They also brought in all the circles they could find!