I’ve been around testing various forum softwares during the years, but since I’m not actively hosting any well visited forum I’m mostly interested in simplicity should the need arise. Amongst the most simplest solutions I’ve found is the Talki-forum plugin for WordPress:  http://tal.ki/

So, I added exactly this forum to my site, it can be found under the “pages” button above in the navigation bar. If you should happen to have anything you would like to discuss, why not start a thread there.