ElkArte is a free, open source, professional grade community forum software package that allows you to set up an online discussion group within minutes.
ElkArte is written in the popular language PHP and uses a SQL database. It requires a minimum of PHP 5.2 and a database backend of either MySQL or PostgreSQL.
FailzBB is a new PHP based OOP forum system. Mainly in use by Exillium, it was started as a small high-schoolers project. Today we see it making turning points and implementing things we wish we saw elsewhere.
Viscacha is a free bulletin board system with an integrated content management system. The intention of the software engineers is to combine the current standards with new and user friendly features. The system supports plugins and components for easily extending the core system. Viscacha uses an
... [More] database abstraction layer to support as many databases as possible. Currently there is only a layer for the open source database engine MySQL. With this software you can easily set up a complete (personal) homepage. The CMS extends the bulletin board system to have a homepage which is connected to the community. [Less]
Internet Discussion Boards is a message board system by Game Maker 2k. Its very easy to set up. Your web host needs PHP and MySQL/PostgreSQL/SQLite. Internet Discussion Boards is Open Source so you can make changes to it.