Place quarters into the case so they can be seen through the holes in the top of the lid. Cover the coins with a piece of paper and close the lid. Take a pencil and push it through any one of the holes. The pencil goes right through the paper and the coin. Everyone can see the pencil has pierced the coin. Repeat with the other coin. And for the grand finale, open the frame and reveal that the piece of paper has punched holes but the coins are unharmed.
 
How did the wooden pencil pass through the solid metal coins without making a hole? Only you know the secret.
 
NOTE:  I believe the website is now defunct, but it does have written instructions