Osymandias displays the Earth as a 3D sphere, using OpenStreetMap tiles. It's an OpenGL program for GTK+ 2 on Linux. There are no releases yet, and it probably won't work out of the box in your environment.

I approached Osymandias as a personal programming challenge, and the code reflects that: it's written by someone who is still finding his way around OpenGL, threadpools, quadtrees, callbacks and other advanced topics. The code is not in the most healthy state, but writing it did make me a much better programmer. One day I hope to release it as a solid piece of work.