The Department of Commerce's United States Patent and Trademark Office (USPTO) will host an exciting, interactive exhibition featuring the top 25 inventions of the 2006-2007 Modern Marvels Invent® Now Challenge, an annual contest that invites independent inventors to share their inventions and ingenious designs with the world.  The exhibition showcases the inventions in an engaging and interactive display of images, drawings, prototypes and finished products.  The Challenge was developed by The History Channel® and Invent Now®, Inc., a division of the National Inventors Hall of Fame® Foundation, and sponsored in part by the USPTO.  The exhibit was unveiled in a ceremony today at the USPTO's Alexandria, Va., headquarters, and will be open and free to the public through June 30.