Visit a corn maze with GPS Global Positioning Systems) units. Ask students to navigate to predefined locations using their GPS. Discuss the concept of a geocache and visit geocaching websites. Hide geocaches for students to find using their GPS (check with the corn maze operator first to make sure this is acceptable). Even easier, set up "virtual geocaches" -- known locations where you do not need to visit the site ahead of time.
Discuss: What are the challenges on finding an absolute location with a GPS that exist in a corn maze, where you are confined to certain predefined routes?