QMentat helps you practice mental arithmetic. It uses arbitrary-length fixed point arithmetic, and can handle any size numbers, only limited by the size of your screen (and in the case of division with an integer result, the speed at which the number can be factored). It is also quite configurable, allowing you to tailor the questions to your needs.
foldroid is a mail folder selection tool. For people who use mutt or a similar text mode mail reader, foldroid is a convenient tool to navigate through your mail folders. It shows how many messages are in each folder and how many of them are new. This, combined with a tool like procmail to sort mail messages of mailing lists into separate folders, makes selecting the right folder to read easy. Foldroid works best when you run it in a screen session, because it then starts every instance of mutt in its own screen.
QSapecNG (Symbolic Analysis Program for Electric Circuits (New Generation)) is a Qt-based program for symbolic analysis of linear analog circuits. It consists of two independent parts, the SapecNG framework engine and the QSapecNG GUI. It was based on SapWin. Users can draw, solve, analyse, and manage analog circuits.
The JsonMe++ (JSON Made easy for C++) library is a C++ wrapper for the JSON-Glib C library. The library makes heavy use of C++ syntactic sugar type C++ language constructs, most notably the subscript operator and cast operator as essential API components, which makes this JSON library extremely simple to use. As a result, access to a deeply nested value from a piece of JSON data can be expressed simply.
libktomgirl is a library that reads a subset of the Tomboy file format. When it's done, it should support reading and writing all aspects of files created by Tomboy, Gnote, and KTomGirl. Despite the K in its name, there are no KDE or Qt dependencies (nor C#, GKT, or GLIB). This is pure C++ with boost and stdlib only. Most of the code is from Gnote.
Deva is a programming language that is small, dynamic, and has some similarities to C and Python. It is designed for embedding in C++ applications, and is also suitable for basic programming tasks. It is written to be as simple as possible, but no simpler. Deva is a multi-paradigm language: it is essentially procedural and imperative, but with support for basic functional and object-oriented idioms.