From PCGS:

Minnesota doubled die quarters were discovered weeks after the coin was released on April 4, 2005 as the 32nd overall issue in the 50 State Quarters series. It was one of those modern error-variety discoveries that many general news media outlets picked up and spun headlines for, only further sending the public into a frenzy over finding the rarity. Demand for the coin is robust, particularly among 50 State Quarters specialists. The doubled die also has a strong following by error-variety collectors, many of whom consider the coin a must-have acquisition due to the celebrity status it attained in the days after its much-publicized discovery.