Maps, Distances, Directions
Distance Calculator (supports locations worldwide)
Perry-Castañeda Library Map Collection: online maps of current interest and general interest.
Census Data Mapper (a simple interface to view, save and print county-based demographic maps of the United States. The data are from the 2010 Census).
For most currencies type "exchange rates" in the Google search box and select currencies from drop-down menus.
Currency Tools (OANDA): currency converter, exchange reates, rates comparison table, and more.
Currency Encyclopedia (currency rates, forex news, and facts for every currency).
For most basic measures type your question in the Google search box, for example: "100 fahrenheit in celsius."
Measurement Converter: conversions various units and measurements, from common to ancient and specialized.
OnlineConversion.com: "convert just about anything to anything else."