Some day when it is pouring rain, gather metal pots, pans, bowls and muffin tins together.Find a spot where you can set up the items and hear the "rain music" as it splatters on them.
Large plastic bowls make a "thud thud" noise which is not as satifying.
Thin aluminum camping pots make the loudest noise.
If you have a camera that records video, you can capture the sound.