The PunchMe applet uses three images. The first shows when the mouse is out of the applet space, the second when the mouse is in the applet space, and the third when you click with the mouse. When you click with the mouse, an accompanying sound file is also triggered. PunchMe can also be put to good use as a tri-state rollover button, so it's one of our toolbox keepers.
Replace the three images with your own, and have at it! See our help section if you'd like to make your own sounds. The applet is also linkable, url and target -- though we've got them shut off in this demo..