At GDC 2006 in San Jose next week Havok will announce Havok FX, a game physics framework for GPUs. There are two talks about Havok FX:

Havok FX: GPU-accelerated Physics for PC Games
Speaker: Andrew Bond
This session introduces Havok's latest innovation for game physics: Havok FX - enabling real-time processing of thousands of rigid-body objects on current and next generation GPUs. Havok's general approach to GPU Effects Physics will be covered, as well as tool-chain requirements and trade-offs with game-critical, game-play physics processing on the CPU.

Physics Simulation on NVIDIA GPUs
Speakers: Simon Green, Mark Harris
Havok FX leverages state of the art software and hardware technology from NVIDIA to extend the capabilities of NVIDIA GPUs and SLI multi-GPU systems to include physics processing for massive real-time effects. In this presentation NVIDIA and Havok engineers will describe how Havok FX utilizes NVIDIA technology to simulate and render thousands of particles and rigid bodies in games. Live real-time demos will demonstrate the high performance available with current GPUs and provide a look into the future of physics processing on NVIDIA GPUs.

Using the GPU to accelerate ray tracing may seem like a natural choice due to the highly parallel nature of the problem. However, determining the most versatile GPU data structure for scene storage and traversal is a challenge. In this paper, we introduce a new method for quick intersection of triangular meshes on the GPU. The method uses a threaded bounding volume hierarchy built from a geometry image, which can be efficiently traversed and constructed entirely on the GPU. This acceleration scheme is highly competitive with other GPU ray tracing methods, while allowing for both dynamic geometry and an efficient level of detail scheme at no extra cost. (Fast GPU Ray Tracing of Dynamic Meshes using Geometry Images Nathan A. Carr, Jared Hoberock, Keenan Crane, and John C. Hart. To appear in Proceedings of Graphics Interface 2006)