Matthias Müller-Fischer from NVidia has shown a nice PhysX destruction demo during GDC, showing fully dynamic destruction. Everything in demo could be destroyed, leaving rubble and smoke which interacted with environment afterwards. Demo was quite taxing on GPU, as it ran at 30 FPS on GTX 680. There was no simulation of stress caused by building's own weight, but team plans to implement that and some other features in the future. With such performance requirements it may require few more GPU generations before similar level of dynamic simulation is used in games, but potential looks very promising.