That video was taken from a weeknight test session they had a couple of weeks ago.
The race is June 20th (Sunday after the 12hr SCCA race). They're advertising 50+ dirt modifieds, with a pretty big purse to the winner (more if it's in a small block car). The rules basically state they must be dirt modifieds and they can only change things that are already adjustable on the cars, and they must use dirt tires.
The support race is a 2 hour Street Stock enduro. I imagine this would be like a big bore Lemons race with the aggression turned up 100x