Somebody was just asking about this. Maybe at the last meeting?
From the IMBA website:
IMBA has renewed its partnership agreement with the National Park Service (NPS), as announced during the National Bike Summit (March 9-11) in Washington, DC. The previous IMBA/NPS agreement, in place from 2005 to 2010, yielded countless hours of volunteerism, enhanced opportunities for youth involvement and new shared-use trails that seamlessly blend with the character of our nation’s parks. The renewed IMBA/NPS partnership will be in place until 2015 and establishes a formal framework for building on existing projects and seeking new opportunities to enhance mountain biking in some of America's treasured national parks.