Bernard von NotHaus and others at NORFED have filed suit against the US Mint for its comment that use of the Liberty Dollar is a federal crime.
"...prosecutors with the Department of Justice have determined that the use of these gold and silver NORFED 'Liberty Dollar' medallions as circulating money is a Federal crime. " -US Mint website.
According to NORFED, "It is not a 'federal crime' for two consenting adults to voluntarily use a piece of silver in trade."
You can find out more about the Liberty Dollar by visiting http://www.libertydollar.org.