A lot of people from different teams/clubs head down there, but in a lot of ways it's just sort of a free-for-all. People show up there knowing that there will be others around, or maybe they'll meet a few teammates to train or just roll around. I'm not sure about when any particular regular/organized rides happen, though. In addition to the evening rides, a lot of people head there before work or at lunchtime.

By the way, I was down there last night, too. It was sort of weird/confusing how the Park Service had half of the point closed off, altering the loop up Ohio Dr. and the Tidal Basin...