Sanity writes "LastCalc is a cross between Google Calculator, a spreadsheet, and a powerful functional programming language, all with a robust and flexible heuristic parser. It even let's you write functions that pull in data from elsewhere on the web. It's all wrapped up in a JQuery-based user interface that does as-you-type syntax highlighting.
Today, LastCalc's creator Ian Clarke (Freenet, Revver) has announced that LastCalc will be open sourced under the GNU Affero General Public License "to accelerate development, spread the workload, and hopefully foster a vibrant volunteer community around the project"."
Link to Original Source