You can never have too many apps. Check out http://apps.usa.gov/. This site collects apps or mobile sites of US Government agencies. The format varies, some are for iPhone, Android or Blackberry, many are mobile-friendly websites.
Smithsonian, National Library of Medicine, National Center for Telehealth and Technology, Department of Energy, FEMA, FBI, NOAA, and National Weather Service are just a few agencies with apps or mobile sites available.
found in the Itunes store. Tactical Breathing Trainer can be used to gain control over physiological and Psychological responses to stress. Many of the techniques taught in this application were provided by Lt. Col. Dave Grossman from his book "On Combat: The Psychology and Physiology of Deadly Conflict in War and in Peace". Of use during finals week at College as well.