MyBB - Forum Software
MyBB is the free and open source, intuitive, extensible, and incredibly powerful forum software you've been looking for.
With everything from forums to threads, posts to private messages, search to profiles, and reputation to warnings, MyBB features everything you need to run an efficient and captivating community. Through plugins and themes, you can extend MyBB's functionality to build your community exactly as you'd like it.
MyBB 1.8.3 is the latest, most up-to-date version of MyBB. If you would you like to download the last release of the previous MyBB release series, you can download MyBB 1.6.16 here.
For me, its the best 1.6 version out there.