GPP is a general-purpose preprocessor with customizable syntax, suitable for a wide range of preprocessing tasks. Its independence from any programming language makes it much more versatile than cpp, while its syntax is lighter and more flexible than that of m4. The syntax is fully customizable, which makes it possible to process text files, HTML, or source code equally efficiently in a variety of languages.
Gentle.NET is a CLS-compliant, database independent object persistence framework. It has an extensive feature set, excellent performance, and reasonably complete docs. It features automatic SQL generation, object construction/caching/uniquing, validation, bindable list support, relation management, transactions, and much more. Oracle, PostgreSQL, MySQL, Firebird/InterBase, MS SQL Server (incl. CE), MS Access, SQLite, Sybase, and Sybase ASA are supported. It includes a NAnt build file as well as VS.NET project files for building under Windows. Mono 1.1.4 and higher is fully supported.
F-Spot is a personal photo management application for the GNOME desktop. It simplifies digital photography by providing intuitive tools to help you share, touch-up, find, and organize your images. These tools include editing, color adjustments, tags, Photo CD creation, and exporting for upload.
SDL.NET is a set of object-oriented CLS-compliant .NET bindings for the SDL gaming library. It provides high-level access to audio, keyboard, mouse, joystick, TrueType fonts, various image formats, sound mixing, MPEG-1 movies, and 3D hardware via OpenGL and a 2D video framebuffer. It is compatible with both .NET and Mono runtimes.
Af-Arch is an N-tier development framework to quickly build high-quality distributed applications. It currently supports C and C# programming languages, which enables you to write client applications using them. It currently runs on GNU/Linux and Microsoft Windows, and is being used in production environments.