Besides the ray tracing announcements from NVIDIA and Microsoft, there's also the Radeon ProRender announcement from AMD. The GPUOpen blog has some more details over here.
AMD is announcing Radeon™ ProRender support for real-time GPU acceleration of ray tracing techniques mixed with traditional rasterization based rendering. This new process fuses the speed of rasterization with the physically-based realism that users of Radeon™ ProRender expect for their workflows.
On a related note, Futuremark said it's working on a new 3DMark test that will take advantage of the new ray tracing API from Microsoft.