Paint3D
This tool allows you to draw something, then rotate it as if it was in 3D space.
I know tools like this already existed, but I wanted to make my own version
UPDATE 2014: 8 bugs fixed, optimized for speed (it's now 5x faster!), added new functionality: Z scrolling, line mode, erase mode, undo rotation, clear board
Point mode | (Hold shift to rotate x axis; ctrl to rotate y axis, scroll to move Z, p=Point, l=Line , e=Erase)