I am a huge fan of open source projects and have contributed to many through github. Here's a quick rundown of projects that I have contributed to.
I also maintain a few of my own open source projects!
Django-seed is a Django development tool that allows you to seed your test database with fake data. This allows developers to focus on the quality of their models rather than spend time punching out test data. The package features an API to seed the database using code, and also a simple manage.py command to seed from the command line.
Drf-generators is a development tool that I wrote while working on APIs with the Django Rest Framework. With drf-generators, one simple command will generate API Views, Serializers, and Urls for your Django models. It can save you tons of time when creating a basic API and allow you to focus on designing solid models.
Mandelb0t is a small twitter bot that generates renderings of the Mandelbrot set and posts them to twitter. I currently have is set up on my Raspberry Pi, posting pictures with a cron job. Eventually I plan to implement more interaction with Twitter users.
This site is one of my biggest ongoing projects. I have built it from the ground up with the Django web framework. I'm constantly learning and improving my programming skills with this project.