Now you just need to read "The Buffon Needle Drop: a Math Activity for Pi Day" in Decoded Science to learn the background, the materials and how to run the experiment.
You will also learn the answer to "What is Pi Day"?
My DeHaan Services article, "One Pi Day Math Activity is the Buffon Needle Drop", adds some advice for math teachers and particularly for math tutors to set up the Buffon experiment.
The Second Pi Day Article is Circular
"One Circular Math Activity for Pi Day" involves measuring accurately, rather than calculating statistical results. It's publicized separately by "Second Math Activity for Pi Day 2013" in DeHaan Services.
The Third and Final Pi Day 2013 Article
One Triple Writing Tip for Pi Day
Two more articles are waiting in the Decoded Science wings.
This does remind me of several previous tips: if you find a topic with a lot of depth, jump in and cover it with several articles.
Even these three Pi Day articles leave a lot of room for more sub-topics and various angles for articles. When you find an interesting topic with lots of possibilities, just go for them!