A simple example showing what happens when you only pay the minimun monthly payment on your credit card debt. I submitted this to Longshot magazine's issue on Debt but my graphic didn't make it in but you can take a look at the other submissions on their site.
US National Debt 1940-2010 [Chicago Tribune]
From the Chicago Tribune found via infographics

Paying Down the National Debt via YouTube
Homemade video trying to show why it is not a problem that China owns part of the U.S. government's debt. Scroll 3 minutes into the video and you can see how he used low-tech paper to explain what would happen if we pay down the debt. No fancy graphics needed.