These events were quite popular when I was racing back in the late 1960s.  Those of us who raced raod courses would do a "gym" now and then.  It was fun, and really safe.  It was also in the era of the Detroit Whale, when sports cars were the only things on the road, besides motorcycles, that had any semblance of good handling.

They were almost exclusively the venue of the sports car puritsts in old MGs, Triumphs, Alfa, etc.  We "foreign car" nuts of that era all marched to a different drummer when it came to our transportation and sport.

Shazzam!  Looks like a potential X-Games competition..