LibreOffice - Calc - LibreOffice Calc is the spreadsheet program you've always needed. A fork of OpenOffice.
Resolver One - Resolver One is a program that blends a familiar spreadsheet-like interface with the powerful...
Excel Formula Beautifier - Beautifies Excel to JavaScript/JSON format.
Vole Office - A light Microsoft Word and Excel editor.
Egeria Planning - Egeria is a free collaborative multidimensional web-based spreadsheet service.
EtherCalc - EtherCalc is a web spreadsheet.