There's http://ethercalc.net/ http://ethercalc.net/ — the subject of the spreadsheet chapters in two previous volumes of Open Source Architecture series at http

There's http://ethercalc.net/ http://ethercalc.net/ — the subject of the spreadsheet chapters in two previous volumes of Open Source Architecture series at http://aosabook.org/ http://aosabook.org/. EtherCalc is mostly in maintenance mode at this moment, and the "99 lines" engine described here is an attempt to simplify its core logic both for educational and refactoring purposes.