Banana Dance Wiki/CMS - Free open source software combining the best of wiki and CMS with community building-features.
LibreOffice - Base - Base, database, database frontend, LibreOffice, ODF, Open Standards, SQL, ODBC
TiddlyWiki - a non-linear personal web notebook
My Visual Database - Using My Visual Database, you can create databases for invoicing, inventory, CRM, or any specific purpose.
DokuWiki - DokuWiki is a simple to use and highly versatile Open Source wiki software that doesn't require a database.
Symphytum - Symphytum Project