We've now taken the girls twice to a local spray park this summer and they love it. It is fun because we have taken them each the past three summers. The first summer, they refused to run through the water and get wet, they just ran around the outside of the spray area enjoying watching the other kids. Last summer, Claire eventually ran through the water and got wet, but Lillian had little interest and instead splashed in a puddle. This summer, they were both a little timid on their first trip, but eventually Claire ran in and got all wet and Lillian followed some time later. When we went for the second time this summer, they both ran right into the water and loved getting wet. It still took Lillian a little bit longer to get her head wet, but she takes after me a little bit like that, I don't mind getting my body wet when swimming, but I don't like putting my head underwater unless necessary, never have.
They have cups in pictures, because just running through water isn't enough. Apparently it is a thing at the spray park, you need a cup to fill with water and throw at the others around you. We actually had a great time our second trip because it was slightly cooler and since it started raining on our way there the park was nearly empty. The rain did stop right before we arrived.