There are any number of questions that can be answered by Wikipedia, but you can add "where am I?" to the list. Given any latitude/longitude coordinates, the WikiLocation API will find you corresponding Wikipedia articles to tell you about your surroundings.
Location is all the rage these days, especially in the mobile world. Geoloqi and its location-sharing Geoloqi API allow developers to easily integrate location awareness into their applications. Its Geofencing API is especially neat, as it allows developers to add triggers based on locations, time, and travel speed, or any combination of the three. It just launched a new site in an effort to reach out to more developers.