eiPie, displayed mathematically in the logo in the upper left, actually consists of three math symbols: e - i - Pi, along with the ending "e" that was added to make the name both symmetric and tasteful. The first "e" represents the irrational* number that is the base of natural logarithms (~2.78). The "i" is the imaginary number defined as the square root of (-1). Pi, normally written as π (~3.14), is the familiar irrational number defined as the ratio of the circumference to the diameter of a circle.
When these three elements are combined together as,
it evaluates to a simple and real value. Thus, two non-rational numbers and an imaginary number, combined properly, gives you a real solution. For those individuals who like math, this combination is one of those things that is simply "cool."
*In the world of math, a number that is irrational is also known as non-rational ⇒ a number that cannot be expressed as a ratio of two whole numbers ⇒ a number that does not have a sequence of digits that repeats over and over again (as any fraction will if divided out and expressed as a decimal). Thus, the meaning of irrational, in a mathematical sense, is not something "crazy", but rather something that is unique and not predictable from what has gone before.