Don't forget to bring a towel
This one was quite fun to shoot. The setup is similar to a typical "splash shot" - that is, you fill a small bag with water (I used a juice carton with screw cap) which gives you a stream of drops at a steady rate. With the camera mounted on a tripod and using an external flash with reflector card, I regulated the flow of water so that it was nearly pouring, but still dripping, making perfect timing less of an issue. The lens was a vintage 55mm Pentax with a 25mm extension tube. Aperture f/8 and shutter speed 1/200th and some of trial and error gave nice results.