Put your iphone on someones body and touch and hold the stethoscope button down. Heart beat will play. The longer you hold the button down the faster the heart beat that is played.
This is a great gag or ice breaker.
"Bet i can make your heart beat faster"
Response to feedback -
Make sure the volume is turned up on your phone. If your volume is low, or your phone is set to vibrate only, you can't hear it. Use the ringer button on left side of your phone. Also make sure finger is not over the iphone speaker located on the lower left corner of your device.