Oh god, why did this shit take me 2 hours:

Anyway, I tried doing it myself first, which ended up in a colossal disaster, then I tried using JScript, which ended up even worse.
So I found thing thing called NCalc and used it.
Except that it also acted retarded so I had to pretty much copy and paste stuff from that project's manual.
There's also an unhandled exception, and I don't know how to fix it.
Anyway, here are the files:
EzhikCalc 2.0:
http://dl.dropbox.com/u/7284637/EzhikCalc.zip
Source Code so that you can laugh even more:
http://dl.dropbox.com/u/7284637/Calculator%20II.rar
Anyway, I probably should drop calculators now, they only bring pain.
Edited:
7 am. What did I do all night? Code a calculator.