Just went to web and typed in Del Mar Racetrack popped up with a number of sites. One has a photo of Bing letting punters in to the track on opening day 1937.
Just now it is the Bing Crosby race season being held over a month.
There is even a Bing Crosby Stakes - a 6 furlong race. Also a Pat O'Brien race (Pat was a co-founder with Bing).
Go look and enjoy the various sites.