Mathematicians and number lovers worldwide will come together on March 14th to celebrate National Pi Day, a celebration of the world's most popular mathematical constant. Pi is the ratio of a circle's circumference to its diameter and while it goes on infinitely, we most often round it off to 3.14. However, today's event starts at 3/14/15 at 9:26 in honor of Pi or 3.1415926. National Pi Day also happens to be the birthday of physicist Albert Einstein so the day can't help but be fun for lovers of math and science. Drop by anytime between 9:26 a.. and 4:30 p.m. and join the fun.