I saw this posted on the Air Travel forum on TA and thought it was such a neat idea. I did a search and it doesn't look like anyone has posted about it here.
It's a free app that, using GPS, you learn about "the world along the path of your flight, hike, or road trip with GPS tracking. Offline geologic maps and interactive points of interest reveal the locations of fossils and georeferenced Wikipedia articles visible from your airplane window seat, vehicle, or hiking trail vista."
It's a product from the University of Minnesota with the National Science Foundation.
I just downloaded it, have NOT used it yet, so nothing to report on functionality.