Last year, I worked on a project with some Olin students to explore building a “dummy GPS.” The idea was to have the simplest possible GPS unit—one where you simply said “I am here,” and then it points back to that location until a new waypoint is set.
Someone went and built one. And manufactured it. As a keyfob.
I think that’s funny.
UPDATE (20081229): This device is actually the Bushnell Backtrack. Above is just a link to a rebranded version that costs $30 more. If one were so inclined, Amazon has them for around $50. There were some comprehensive (fairly negative) reviews at Amazon that seemed to indicate that this is useless for mall parking lot navigation. However, I can still see this device as being useful to campers/hikers and the like. That, and there is more info at the Bushnell site.