I’m continually impressed by the things I can do with Google.  Today I learned about their calculator, which can do all kinds of magic stuff.  For example, if you enter “2.3 billion acres to square meters” on the Google search line, pressing the Search button will return the answer (9.30776977 x 10¹² square meters) as well as a bunch of links to unit conversion calculators, dictionaries of weights and measures, etc.  Dang, that’s cool.