Office Applications

AbiWord

AbiWord is a free word processing program similar to MS Word.
http://www.abisource.com/
http://www.abisource.com/download/

OpenOffice.org Office Suite

Wordprocessor, SpreadSheet, Database, Presentation, Illustration
http://www.openoffice.org/
http://download.openoffice.org/index.html

Portable OpenOffice.org is a fully functional package of OpenOffice.org optimized for use on a USB key drive.
http://www.portableapps.com/apps/office/openoffice_portable/

LibreOffice

LibreOffice is a free and powerful office suite, and a successor to OpenOffice.org (commonly known as OpenOffice).
https://www.libreoffice.org/
https://www.libreoffice.org/download/download/

Portable LibreOffice is a fully functional package of LibreOffice optimized for use on a USB key drive.
https://portableapps.com/apps/office/libreoffice_portable