Timehop is an interesting idea. It goes through your social history, Facebook, Flickr, Twitter, Foursquare, and even the photos on your phone and looks for events. It will then show you what you were doing on this date a year ago, or more. It's your own personal "This day in history" app.
Posted by Jeff Scott on October 23rd, 2012
iPhone App - Designed for iPhone, compatible with iPad