Stack Exchange, a spin-off of the popular Stack Overflow programming Q&A site has an “Area 51″ staging site, where Dave Houlker recently proposed a new site Q&A for SDL Tridion.
You can move the potential site into a beta phase by committing. Just follow this image link.
Full disclosure: I get credit if you click the nice image. Join via aÂ non-referring linkÂ if you prefer.