I've added a new freebie to the Marketplace:
This player has a bunch of settings you can configure:
One neat aspect is that it can choose at random (or in sequence) from up to three different sounds. It can "throw its voice" to some other location in the scene. You can add a delay before playing and specify how long to wait (default 5 seconds) between triggerings.
All you really need to do is plop a floor mat on the ground, put the floor sensor script in it, give it a sensor name (e.g., "Floor1"), toss this script in another (or the same) object to play the sound, use the same sensor name (or a comma-separated list of them), choose your sound(s), and then tinker with the other settings to your tastes.