Last week I gave a talk at GDC on “Light probe interpolation using tetrahedral tessellations”. Here are the slides and this is the accompanying video:
The talk describes a technique for light probe interpolation, which I believe has some advantages over the typically used “a bunch of OBBs filled with regular grids +per probe visibility info”. To see how it works in practice, you can download Unity 3.5 and give it a go. The video was captured from Shadowgun, the first game to use this approach.