This tool is a replacement for the GUID Generator (guidgen.exe) shipped with Visual Studio, and can generate additional GUID formats.
Instead of displaying the GUID as a hexadecimal value, the GUID is ASCII encoded into a smaller string due to the higher data density of ASCII.
The GUID in hexadecimal format:
c9a646d3-9c61-4cb7-bfcd-ee2522c8f633
would after encoding be:
00amyWGct0y_ze4lIsj2Mw
The code is based on Mads Kristensen's blog post.