If you enjoy skeumorphic calculators with their data interfaces, and haven't already, look into the RPN[1] notation used in (most, I believe) scientific/programmable calculators. Once you go there, you stay there. Just Google[2] or DDG[3] for it to play around.
1: Wikipedia entry: https://en.wikipedia.org/wiki/Reverse_Polish_notation
2: Google search: https://www.google.com/search?q=rpn%20calculator%20online