I've been doing quite a bit of general bugfixing in Godot lately. I've worked with the engine in one way or another for quite a few years now and contributing to open source projects is always very rewarding.
Simple Chip-8 emulator using SDL2. I wrote Octo to teach myself emulator programming. I'm not very sure it was very successful really, it's and extremely simple system and very, very easy to emulate.