Mapfaire...the easiest way to create an awesome map http://ow.ly/5eoww (via Free Technology for Teachers)
Historvius...helps you discover the world's historic sites http://ow.ly/5fkyG
Intersect....capture experiences in time and place & connect to people who cross your path http://ow.ly/5CUIX
Geotrio.... Search for tours, take them, and share them with your friends http://ow.ly/5ZrIc