Falling Objects Sound

I'm trying to make some wooden crates make a crashing sound when they colide with both the floor and or terrain and with each other, so I guess I might need three different sounds but how do I script this?

Just to get you started... http://unity3d.com/support/documentation/ScriptReference/AudioSource.html audio.Play();

Then you'll be using some sort of collision detection in your script http://unity3d.com/support/documentation/ScriptReference/Collision.html