ThorPy is a GUI library for the excellent pygame, which is a python library based on the SDL. Pygame is a library for games and applications coding.
ThorPy is written in pure Python (2.7 and 3.X) and is therefore available on all plateforms for which pygame is available. However, for some optional effects like blur and shadows, you will need NumPy and PIL (see installation tutorial for more).
The library is free, open-source and distributed under the MIT License.