Pi Day is an excuse to celebrate maths, but while doing so take the opportunity to combine it with some books.
Pi represents the relationship between a circle's diameter and its circumference. Why was a Greek letter used to represent this relationship?
Cindy Neuschwander, an American teacher who has written several books about Sir Cumference has found a fun way to extend children's understanding of maths concepts. One of her books is called Sir Cumference and the Dragon of Pi. Here Sir Cumference drinks a potion which turns him into a dragon and his son Radius has to search for the magic number known as pi which will restore him to his former shape. If your library doesn't have this or you want something simpler use a book about shapes, such as those by Tana Hoban, Circus by Lois Ehlert or the newer Shapes That Roll by Karen Berman Nagel.
To celebrate Albert Einstein's birthday either do some research in factual books or locate a biography of his life such as Odd Boy Out by Don Brown.