Free Time

So I've obtained a bunch of free time. I want to extend my knowledge of C++, Java, and Python. I know the languages, but I think it is time that I learn libraries so that I can actually make stuff.

Also, anybody know any cool open source groups that I can join so that I can actually use my new skills?

As for my background, let's say I am really good at physics and math.

I'd recommend actually using free programs and noting some of the defects or other general improvements. Otherwise, you could probably visit some Linux forums and note some of the defects that other people have noted.

If you intend to publish your code to the software maintainers, you ought to contact them first and find out their attitude to accepting code.