Last year Cyril Crassin presented a voxel based approach for interactively computing indirect diffuse and specular lighting, along with a couple of demonstration videos, and kept working on the matter since then.
In this talk given in May at the NVIDIA GPU Technology Conference, he briefly explains the technique:
Interestingly enough, as he points out, the technique has been implemented in the Unreal Engine 4 already.
Last weekend the demogroup Mercury released at Tokyo Demo Fest the final version of their invitation to the upcoming Revision party: a 64kB demo called Epsilon. While the complexity of the scenes is very limited, the rendering, seemingly a raymarching shader, features a couple of very noteworthy real-time effects including ambient occlusion, reflexion (up to two iterations it seems) and refraction, caustics, and an hexagonal bokeh depth of field.