According to the New York Times, 20th Century Fox hired Franklin Mint (you know, the company behind all those great commemorative coin offers) "to place a full-color image of the Silver Surfer, complete with Web address, on the backs of 40,000 California statehood quarters."
The United States Mint was kind enough to point out that advertising on coins is illegal. Per the article:
M. Moshe Malamud, chairman of the Franklin Mint, denied that what the company put on the coins was an advertisement. He said it "enhanced" the coins to make them "commemorative," as it did a few years ago when it added images of Elvis Presley to millions of Tennessee state quarters.
Somehow, I don't think Elvis was trying to get people to buy tickets to his next show.