configuration management for spreadsheets

OpenDocument Spreadsheet (Flat XML) (.fods) format in OpenOffice 3.0 is a great source format for spreadsheets. It’s human-readable XML, it’s good for “Save As…” into Microsoft Excel 97/2000/XP (.xls) format.

Best of all, it allows you to easily configuration manage your spreadsheets (along with meaningful textual diffs) using Mercurial, git, etc.