Is ActiveSheets actually available somewhere? Probably my #1 complaint about CS papers in general is that they present something interesting and fancy that you usually can't get your hands on.
Did you investigate using LibreOffice Calc instead of Excel?
we didn't look specifically at libreoffice, but we considered a number of other free or online spreadsheet offerings. excel is attractive because there's a widely installed user base. we are however considering integrations with other spreadsheet offerings. we hope to have a free activesheets service available for trial.