Yes, you knew it was only a matter of time before Commoncraft explained AR in their friendly and succinct style. The above video lists some generic applications of augmented reality mostly relying on data overlays. Apps like Layar can overlay a broad variety of information, from shopping and real estate (try the Google Places layar) to art and education (MoMA exhibit). Searching through available layers for education reveals a number of campus and library tours, but these sorts of apps can support much more relevant, place-based learning opportunities, like the layer featuring POIs for Black History Month (for the Baltimore and DC areas). Another example is PhillyHistory AR which overlays images of historic Philadelphia over the view Philly on your phone (more about this project at phillyhistory.org).
Finding layers in your area can be challenging if you’re not near a large city or popular destination. Look for the Panaramio, AllMenus, or Earthquake layers which are more likely to contain something captured in your area.