GoAccess is a real-time web log analyzer and interactive viewer that runs in a terminal in *nix systems or through your browser.

LICEcap simple animated screen capture tool for Windows and OS X

SQLiteC++ (SQLiteCpp) is a smart and easy to use C++ SQLite3 wrapper.

a clean C library for processing UTF-8 Unicode data

WavPack encode/decode library, command-line programs, and several plugins

MP3 player for small children - firmware & PCB schematic