I've contributed to a few Python projects, and the experience I had with the IPython and beets groups both stand out in my mind as very friendly. The patch I contributed to IPython was vanishingly trivial. It removed an unnecessary function call in a code path that wasn't even performance-sensitive (I just stumbled on it when looking into a more complex issue). I would have understood if the patch just lingered without being looked at for ages. It didn't address an existing issue, didn't impact the correctness of the code, and barely had any consequence to performance. But, it was quickly reviewed and accepted and the maintainers were thankful to have my contribution. I was very pleasantly surprised, and will certainly consider contributing to their project again when I have time. Likewise, I ran into a bug in the beets MP3 tagging/collection manager and was able to report the issue, discuss it with the author and other contributors to determine the preferred way to handle the situation, create a new unit test and fix, and get it accepted all within a couple of days. Everyone I spoke with was very inviting and helpful. I hope to be able to help them again in the future as well!