The Irrlicht Engine is an open source high performance realtime 3D engine written and usable in C++. It is completely cross-platform, using D3D, OpenGL and its own software renderers.
LinuxOS from ubuntu, customisable for everyone, social and media
Ubuntu based GNU/Linux system, use Gnome Shell.
Easy for learn Linux and programming.
All software of everyday use.
Wine and Virtual Machine for use other OS.
db4o is the world's leading open source object database for Java and .NET. Leverage fast native object persistence, ACID transactions, query-by-example, S.O.D.A object query API, automatic class schema evolution, small size (http://developer.db4o.com)