Actually the penny is referred to as elongated coin, but Dennis Berry likes the sound of "squished". It's highly, highly, highly addictive; almost as bad as collecting slot cards.

Usually you place two quarters + one copper penny (pre-1982) into a machine and it spits out just the elongated penny. Here's a picture of a machine that elongates the coin along with a completed penny. A website link is at the bottom to get you started on this slippery slope:

http://www.pennycollector.com/