How do you get a dent out of a ping pong ball?

Answer 1

The heat from the boiling water warms up the air inside the ping pong causing the air to expand and push the dent of the ping pong back out.

Answer 2

Try sucking on it strongly! It works sometimes! For more/better alternatives, see Related links below this box.

Drop it in hot water. The heat causes the air inside to expand and can pop it back to shape.