Today only, Microsoft is offering Office 2010 Starter edition as a free download from their web site.
Microsoft Office 2010 Starter is typically only offered with select new PCs. It includes limited versions of Word and Excel, and is designed to rival free alternatives such as LibreOffice. Unlike other versions of Office, it is an ad-supported product.
The download is a click-to-run application, which downloads and self-updates in an on-demand basis.
Download: Microsoft Office 2010 Starter (EXE)