Beast is a new light-weight forum built with Ruby on Rails.
The simple design is great, and let’s the user discussions take center stage unlike most forums.
Take a look at Beast’s thread view page compared to vbulletin’s.
Vbulletin’s thread view page is bloated with useless features, while Beast’s is clean and easy to read. I wish more forums were designed this way, like the good old days of Yabb and Ikonboard.