X-Plane is a flight simulator that reads in the geometric shape of any aircraft and then figures out how that aircraft will fly. It does this via an engineering process called "blade element theory", which involves breaking the aircraft down into many small elements and then finding the forces on each little element many times per second. These forces are then converted into accelerations, which are then integrated to velocities and positions. This gives X-Plane the most realistic flight model available for personal computers.
Motorsport is a project with a clear goal: to create the most realistic vehicle simulation possible. This includes cars and trucks, which can be driven using common input devices such as keyboards and steering wheels. It limits realism to what the hardware, and is intended for hardcore driving simulator fans. This means that it will try to have realistic physics, but not necessarily 'playable', 'easy', or 'fun' physics - these characteristics will depend on which vehicle is driven and on what a person is trying to drive it.
Biogenesis simulates in a visual fashion the processes involved in the evolution of unicellular organisms in nature. It tries to be a didactic approximation to the ideas of mutation or evolution, and can be enjoyed also as an entertainment. It's intended to serve as a support to show students some basic biological facts. The idea of Biogenesis is taken from Primordial Life, but it's an independent project.
Brain Workshop is an implementation of the Dual N-Back mental exercise. This exercise is a mental activity that has been scientifically shown to improve your working memory (short-term memory) and fluid intelligence. The game involves remembering a sequence of spoken letters and a sequence of positions of a square at the same time. Brain Workshop includes additional challenging game modes beyond Dual N-Back.