Google Spreadsheets and XPath
In Excel you can import data from web pages using some macro. I thought that was cool and used it extensively in some financial analysis documents. Unfortunately for me, I moved those documents to Google Spreadsheets and had to redo all of those macros with the equally boring, albeit useful, importHTML function.
Wait, are you freaking kidding me?! Yeah, that function is totally trumped (in my opinion) by the importXML function. This function allows you to use arbitrary XPath queries on any URL! That's just über geeky cool.
Although I don't have a need for it (yet), there is also an importFeed function, which acts in a similar way but pulls in RSS or Atom feeds.
Check out the reference documentation for all of the import functions.
Google, (sometimes) I really love you.
