Pi is the ratio of a circle's circumference to its diameter. The actual decimal place value is infinite, but most middle school teachers allow you to abbreviate it at 3.14. That makes "Pi Day" March 14. On this day, teachers plan activities that relate to the number pi and challenge students to think outside of the (circular) box.
Pi Memorization Contest

Challenge your middle schoolers to remember as many digits of pi as they can. You can hold a contest where each student has a chance to recite pi  whoever remembers the most numbers is the winner. The prize could be a "pinapple" or a "cream pi."
Pi Line Up

Hold an assembly where each student in the school is given a paper plate and must decorate that plate with an assigned number. Once the students are finished with the plates, you can go outside and create a long line of students, placing them in "pi order" with their plates.
Value of a Pizza Pi

Call the local pizza parlor to learn how much various pizzas cost. In math class, students can use their pi skills to determine how many square inches are in each pizza and how much each square inch costs, based on the pizza's price. From there, you can determine which type of pizza is the best deal.
Piku

English teachers can get in on the action too. Ask students to write a "piku" instead of a haiku. The concept is similar to a haiku, except that it is only a three line poem  the first line is three syllables, the second is one and the third is four.
Pi Necklace

Give students a printout with the value of pi to several digits. Using that as a guide, students can assign each number a different color and string beads according to that pattern.
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