Nerdy bakers have a particular reason to love March 14th. Tomorrow's date, 3/14, resembles the mathematical constant of pi (3.14159). And what better way to celebrate pi than to make pie? Today we're making pies to share with workmates tomorrow. We're thinking of a basic apple, and a more adventurous chocolate one, which together will please a variety of palates. But since Pi Day is an invented holiday, there are few rules, so feel free to celebrate with a savory onion pie, a quiche, or even a tart.