Quicksilver Forums is a fast, feature rich bulletin board system.
It is fully object oriented and optimized for speed, ease of use, and easy modification.
It checks all inputs though a common interface, which drastically reduces the chances of exploitable bugs.
A powerful and flexible skinning engine makes giving your board a new look very simple.
An advanced permissions system allows for fine-grained group and user permissions.
It is based on the popular MercuryBoard software.

Though I suspect not many people are still watching.... it can be downloaded here: http://code.google.com/p/quicksilverforums/
Or at Sourceforge, apparently my access to the project entry still works: https://sourceforge.net/projects/qsforums/