I found this really cool cross-platform toolkit for making GUIs from Python! It’s named Kivy. It’s available on Windows, Linux and Mac. (In case you’re not a developer, this is very cool!) The official installation instructions are here: https://kivy.org/docs/installation/installation-windows.html

However, I got an error when it tried to install gstreamer. I had to install that separately. What I did was download the wheel (.whl) file and install it first. After I did that, the rest of install worked fine. You can download the wheel file from here:
https://www.googledrive.com/host/0B1_HB9J8mZepNzZ5aW91Q0tJU2s/kivy.deps.gstreamer-0.1.5-cp27-none-win_amd64.whl

Open a command prompt/shell (of your choice), change to the directory where you downloaded the file and run:

pip install kivy.deps.gstreamer-0.1.5-cp27-none-win_amd64.whl

Note that I got an HTTP 502 error (yes, 502, or “temporary error”) for a while this morning, but then it worked. However, if that file does not exist (an HTTP 404 error), please check this page and download the appropriate file for your version of Windows and Python:
https://kivy.org/downloads/packages/simple/kivy-deps-gstreamer/

Finally, proceed with running everything from the official instructions. (Or everything that failed on you, if you’re sure what that was.)

Happy GUI development! 🙂