A Forth compiler with a little difference
Scientific/engineering firmware repurposing HP business calculators!
Desktop RPN calculator
A suite of RPN calculators and a class library for Object Pascal
End User Tools for Windows.
Terminal calculator with differential error estimates
An HP RPN calculator with interval output
RPNCalc - The command line Reverse Polish Notation (RPN) Calculator
ASCII SpaceInvaders, Pacman, Frogger, + 10 puzzles
Fast Win32 math & science tool
Simple Java computer algebra calculator
financial, statistics, scientific and programmers calculator
Simple RPN desktop calculator, implemented with wxWidgets and Lua.
ultimative units calculation and conversion tool and library
Rpn calculator, string and macro based
Reor is a winsome calculator with loads of functions, by Ajay Menon.
An RPN command line calculator.
galculator is a scientific calculator in algebraic mode and RPN
A functional HP-style command-line RPN scientific calculator
Idea bank for projects using MonoDevelop
I believe it is the best tool for everone get it it's free.