If you have Mac OS X you can start the calculator just by clicking
Warning: when you launch for the first time you will getting a message warning you that I don't have a valid certificate (they cost a $100 or so) and asking if you still want to start the program. Ignore this warning.
After the first time: You can start the program either from this web page or just by executing javaws.
Credits: Joe Dane and George Wilkens were key in getting the C code compiled and linked.