DES COURTNEY So ugly, it's beautiful. I've been using MathPad since the time it was a "exclusive" item for the old DiskWorld software magazine. While the UI hasn't aged gracefully, this "poor man's Mathematica" really is a versitile and useful math analysis tool. I used it heavily for my math heavy CS courses in grad school, doing things like parameterized functions and matrix math. I still use it to this day for occasional "what if" graphing anaylsis, since Apple's old Graphing Calculator was crippled in comparision.
(Version 2.6.4)