Lua for Windows
At the point I was working on Sigma/C++ instead of Sigma/Python, I was using the simple-but-beautiful Lua as my scripting platform.
The Windows package now includes wxWindows with native bindings. This makes it into a dangerous competitor to Python for rapid-prototyped GUIs.
I wish Python’s packages (especially for Windows and probably for Mac) would at least provide the option to install wxWindows automatically in the right place with all the right symlinks and stuff.