NASA data science project, cooked up in 2 days for a hackathon. Predicts rainfall probability given a location and date.
Simple "Machine Learning" framework written in C. (Also has python bindings that do not work on windows -> MSVC is bad). Only ships with KNN and Simple Linear Regression for now.
Very Simplistic software rendering library written in C aiming to support as wide of a range of systems as possible (by not depending on C std lib).
"build system" / reciper builder for C in C, with other helpful general purpose and misc utilities that ports useful features from more modern languages.
Simple programming language VM implemented in C. still very undeveloped but can print hello world and parse basic math functions :)