Inspired by Max Berry's book, Jennifer Government, NationStates is one of the most popular online simulation games. The forum boasts over 5 million posts and 200,000 users.
The Raspberry Pi is a cheap, credit-card sized computer. The official website uses phpBB for their discussion forums.
Info-Mac is a community dating back to 1984 as a mailing list and was the first online community for Apple's Macintosh computer. All of their content was converted to phpBB in 2007.
Discussion board for the massively popular xkcd web comic. Covering everything from Maths and Science to Logic Puzzles and Forum Games. Over 100k members and 2.4 Million posts.
As the official board for the world-famous band Queen, this community hosts a wide variety of discussions by Queen fans from around the globe.
Gentoo Linux is an open source operating system built on top of the Linux kernel and based on the Portage package management system.