My "bored in class" story: In addition to plenty of stickman fighting animations, I wrote a full "Geometry" helper program which solved arbitrary triangles, did the quadratic equation (including imaginary roots), and maybe one or two other things that I don't remember.

We could have a quadratic equation solver on tests, but not the other functions. I put a splash screen that said my name and "Quadratic Equation Solver" which prompted a, b, and c if you pressed ENTER. If you pressed the right button on that splash screen (sin, naturally) it would unlock the full menu.