HP-15C Torsten Manz
[http://www.hpmuseum.org/simulate/15_1_201.zip]
Torsten Manz has written a GPL'd HP-15C simulation entirely in Tcl/Tk. This version requires one install the included HP-15C simulation font.
HP-15C Torsten Manz and [Larry Smith] [http://www.smith-house.org:8000/software/IQ-15C.tcl]
Larry Smith took Torsten's work and added a version of LCD hexa panel and removed the need to install a font. I also changed the name to IQ-15C, since Torsten's version was so faithful to the actual calculator I got nervous about trademark issues.