Martinsh has come up with some amazing screenshots of a mountain landscape in the Blender Game Engine, which utilizes some of the new 2D filters being developed. The landscapes are some of the most impressive and detailed pieces of art I've ever seen in the BGE.
Martinsh has been working on integrating a bunch of new GLSL filters, including Chromatic Aberration and SSAO (Screen Space Ambient Occlusion), among others. The SSAO is particularly impressive (see top right image below), which Mike Pan (mpan3) helped to develop. This demo uses SSAO+sunrays+chromatic_aberration+DoF.
Theres a thread on Blenderartists.org with full sized pictures detailing each individual component of the realtime rendering, the thread is also good for keeping track of updates and leaving comments/questions.
On a final exciting note - Martinsh has just released the .blends earlier today: Download link - Link(1)
The 'game' controls:
"WASD - move camera
Left/Right arrows - move sun
1 - SSAO only
2 - SSAO + scene
3 - Light scattering
4 - DoF (mousewheel - change focus)
5 - Chromatic abberration
6 - Cross shaped bloom"
Of course make sure to realize all of this is very new and requires a very powerful computer to run properly. Martinsh is hoping to optimize the filters more soon, which will be made a lot easier when downsampling gets integrated.