I found some inspiration in the Stuck?! Sketches challenge for January, the first sketch they have on their blog, for this layout.
The photos are of my nephews playing with water balloons, on a hot summer day. Firstly they were bored, but also they were hot, so what better way to entertain them and cool them down at the same time. Sadly the water balloons didn't last for long, but they had fun.
So on my layout, I used a radiant rain dauber to make the "water splats" in the background.