Dr. Geo is an interactive geometry program that is distributed as a universal portable application. It allows one to create a geometric sketch and manipulate it according to its constraints. It is usable at home or at school, in primary or secondary education. It is simple and effective with extended features including scripting and programming.
LinuxMCE is an add-on to Kubuntu that provides a complete whole-house media solution. It provides PVR and distributed media functions. It is stable, easy to use, and requires no knowledge of Linux and only basic computer skills. It allows you to set up a computer system that centralizes audio/video equipment, allowing you to access all media functions in other rooms with only thin clients. It supports home automation protocols including KNX, EIB, Z-Wave, DMX, EnOcean, and PLCBUS.
Arx Libertatis is a cross-platform, open source port of Arx Fatalis, a 2002 first-person role-playing game developed by Arkane Studios. Arx Fatalis features crafting, melee and ranged combat, and a unique casting system where the player draws runes in real time to effect the desired spell. The Arx Libertatis source code is based on the publicly released Arx Fatalis sources. This does however not include the game data, so you need to obtain a copy of the original Arx Fatalis or its demo.
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.