OgreSocks is an OO wrapper around WinSock (the Windows Sockets dll), aimed at applications built using Ogre, the OO Graphics Rendering Engine (www.ogre3d.org). OgreSocks is released under the LGPL.
SAGE stands for Simple Asynchronous Game Engine and is an attempt to implement a multithreaded game engine in C#. For rendering/physics/sound/etc it uses(/will use) open source libraries (like OGRE, ODE, etc) through plugins.