Shows the position of the sun at any time and location. See also The Photographer's Ephemeris, which is slightly less intuitive. Very similar to suncalc.org is suncalc.net - but it's not working at the moment after Google made changes to the charges for the Google Maps API.
List of locations worldwide, with spelling variations in multiple languages and scripts. Very comprehensive, drawing from multiple sources
Allows map, satellite, and Street View in Google Maps to be displayed simultaneously
Gives the area of a shape you draw on a Google map
Helps estimate maximum crowd density for a selected area (French)
Dropdown gives access to several map platforms; also has weather layer
Provides detailed 3D views of mountains worldwide