The Webware weblog highlights 5 things you didn't know about Google Docs and Spreadsheets, most notably that you can insert live lookups in Google Spreadsheets via Google search and Google Finance.
Using two special formulas, users can create cells that will update constantly with data or information gleaned from Web searches or Google's finance service. This works for things such as stock symbols, sports statistics, or any other piece of information you want to source and keep up to date automatically
For example, you can insert the current price of Google stock in a spreadsheet by entering
=GoogleFinance("GOOG"; "price"), or check out the number of internet users in Paraguay with
=GoogleLookup("Paraguay"; "internet users"). Very cool.