This is a forum. It runs on JS and some API calls. Just put the forum.html file somewhere and use it and you have my forum.
To have your own forum, make a copy, create yourself a Firebase database, a Disqus forum, replace mine with yours, and put it somewhere.
For bonus cool points, drop the file into dataurl and you will get a huge URL which you can then pass to tinyurl and end up with a forum that has no hosting (at least none you pay for) like http://tinyurl.com/reallyreallymagicalforum
The only problem with that approach is that comment counts on threads will not work.
Uses bootstrap, JQuery, Frebase, Disqus and jPages (http://luis-almeida.github.io/jPages/)