Downward-Directed Crepuscular Rays
We often see crepuscular rays with an apparent upward aim. In this case, the chunky young anvil from a nascent supercell spread across that part of the sky containing the sun, part of which can be seen through a hole in the cloud. As with other crepusculars, the rays actually are parallel, but seem to spread away from each other due to a bit of optical trickery--our brain's (or the camera's) flattened projection of a three-dimensional scene.
Okeene OK (29May 12), looking WNW.