Meedan.net - Arabic-English forum
Not controversial, but politically-motivated.
Saw the launching of this cool site a few days ago:
An Arabic-English forum using Machine Translation with expert corrections
Essentially people post links about arabic-world related news to the site in either arabic or english. It uses machine translation to start the translation from one to the other, and then various human editors come along to touch up posts and comments as they can. The site shows english and arabic side by side. The idea is to foster more communication between speakers of both languages. Pretty neat.