Google Spreadsheets

Spreadsheets you can work with on the web, so easier to share and publish than Excel.

Add your comments or examples of something you've done here.

There's also GoogleDocuments (Google now group them together).

And here's a link to Google's tour http://www.google.com/google-d-s/intl/en/tour1.html which seems to indicate that you can publish direct from a Google doc to a web log . . . hmm, interesting. More on that soon too.