http://forum.griffinsoft.net/A new forum, but a very good one and worth joining. It has an excellent lay-out and works well. It basically covers a lot of topics, and has a "Spam" section for people who like to make useless posts for fun. It also has a programming section for people to talk about their programming skills.

http://www.worldofmi.com/forums/index.php A forum that focuses on the Monkey Island series of point-and-click adventure games.