Project Ouroboros
This is an ongoing project to develop techniques to do orbital mechanics using python. I know that there are existing libraries to do physics simulation, but I wouldn't learn anything if I took something off of the shelf. In working on this, I've taught myself numpy, matplotlib, sympy, and some vector calculus.
I was inspired to start this project because of my love of Kerbal Space Program, a game notable for fairly accurate orbital simulation. The conclusion of this project will hopefully be a tool to predict stable solutions to the n-body problem, but that is going to take a while.
For more information, check out this project's github.