An ever-growing set of weights, measures and units conversion/calculation modules. Allow users to discover things like how many seconds old they are, the difference between a gallon in the USA and a gallon in the UK, how many nanometers in an inch, how many quarts in a chaldron, etc.
How Many?: A Dictionary of Units of Measurement
A dictionary which includes all the units of the International System (SIPM) and many other units of the metric system used in everyday life or in science.
Universal Currency Converter
Converts money at the current exchange rate.
Calculators for all kinds of applications.
Compare the cost of living in hundreds of U.S. and international cities.