Pi is the ratio between a circle's diameter and its circumference. While we commonly think of it as 3.14, it's actual value is so irrational and transcendental that it would carry on indefinitely past its decimal point forever. Pie, on the other hand, is a sometimes circular, delicious pastry that is unfortunately limited to the size of whatever pan its baked in.
I'm not enough of a math wiz to figure out whether or not there is another sort of numerical link between the pie and pi, but I do know that today is March 14th, or 3.14 on the American calendar—and that similarity seems like a good enough reason to make a pie to me. Is that irrational? Maybe, but then again, so is pi.
Here are 16 recipes to make today to express the somewhat irrational, but definitely constant, desire for pie. No calculator necessary.