Remember NVIDIA's Endless City demo? Here is how NVIDIA describes it:
Take a cruise through the most complex city ever rendered in real-time. NVIDIA’s Endless City harnesses the horsepower of our incredible tessellation engine to procedurally generate urban detail never before possible in an interactive world. Sit back, relax and enjoy the view.
More here > Demos > Endless City.
When it was released, this demo wouldn't run on Radeons because it required CUDA, but it wasn't clear what CUDA was used for exactly. As it turns out, it's not used for anything at all, at least according to Scali's latest weblog post. He found out that you can disable CUDA as well as a vendor check, and the demo runs just fine on any DX11 card, though apparently not very fast. He's even uploaded a patch to make it easy for everyone.