Best to check the water conditions with the park office or on the Pine Ridge Association website before planning any activity that involves crossing Coyote Creek.
China Hole is a popular seasonal destination for swimming / picnicking. It's a beautiful rocky area at the confluence of two creeks.
Most runners will start China Hole Trail headed down from Manzanita Point. Along the way, there are fantastic views of the nearby canyons, and if done in the spring lots of wildflowers. It's a reasonable ~1000 ft descent, just remember that one does have to climb back out :)
The other end of China Hole Trail is the descent from Mahoney Meadows Road down to China Hole. This approach is more remote and typically less-traveled.