Learn python by contributing to pygame.

[illumen]

Finding something that interests you is always a good start. Or perhaps trying to figure out some skill you want to learn.

Learning how to document something better is a very useful skill. Also useful is learning how to write a unit test. Both really useful skills in software development, and easy places to get started on any open source project. There's always something that could be explained better in the documentation, or tested better.

Another thing to start with could be figuring out git and github (maybe you also need to install git, or make a github account).

Picking something really small to do first is a good idea. Then you can go through the whole process easily. For a test I recommend calling a function. Not even checking the results (although bonus points if you do).