Dolibarr is a simple Web application with ERP and CRM capabilities. It is designed for small and medium companies, freelancers or foundations, and can be used to deal with all things you require to manage your activities, such as management of products, stocks, commercial proposals, invoices, orders, members of a foundation, and mailings. A single executable that installs the server and database is available for people with no technical knowledge.
Chyrp is a blogging engine designed to be very lightweight while retaining functionality. It has powerful theme and extension engines, so you can personalize it however you want. The code is well-documented, and it has a very strong structure that's loosely based on the MVC design pattern. Chyrp allows importation from several different blogging engines and uses a system called "feathers", which are basically templates for custom posts.
Qtnp is program for math\physics teachers and students. There 4 tools: Pen, Line, Jogged line, and Circle. The software can draw grids, coordinate planes, and graphics. It has flexible settings, presentation mode, support for all base formats, a GUI for blackboards/tablets, and a built-in powerful calculator.