Google Apps: https://play.google.com/store It let's you store your music and videos. It could be useful to me as a student if I needed to store something for an assignment.
https://maps.google.com/?hl=en This app lets you find locations on a map. It could be useful if I ever need to know the location of a school event.
http://translate.google.com/?hl=en This app translates things from different languages. It could be useful if I ever take a foreign language class.