Are you looking for races or workouts or group events? I am in the Eastern U.S. time zone and there are almost too many rides. It's like scrolling through Netflix. If there were only a few, I'd just pick one and be done with it.
Of course, workouts and solo rides can be done anytime you like. Throw in the climb portals and robopacers and I really have a hard time deciding. Events like Tour de Zwift run every hour.