In 2008, the Richardson Farm maze featured a design celebrating the U.S. Presidential elections. At 28 acres and 11.1 miles of trail, it was billed as the World's Largest Corn Maze.
Visitors are given a 9x6 inch postcard map of the maze. This maze featured 24 checkpoints. At each checkpoint, a hole punch tool is used on the postcard map. Each hole punch leaves a different shaped hole to verify if you visited the checkpoint.
http://www.cbsnews.com/video/watch/?id=50156553n
2013 maze - 50th anniversary of Beatlemania
2014 maze - 200th Anniversary of the Star Spangled Banner