Do you mean to say you can't find any place at all in the Bay Area (I'm assuming that you mean San Francisco Bay Area) to go social dancing, or that you can't find a place where people actually dress up fancy to social dance?

As far as dressing up goes, there is a series of Victorian-style balls called the Gaskell Ball where people get REALLY dressed up. See http://www.gaskellball.com/

And then there's the San Francisco Black & White Ball, but I hear not many people actually dance at this even though it's very fancy dress and very large. See http://www.bwball.com/home_main.html
Palo Alto has its own Black and White Ball on October 2nd, but I don't have a web site address for that.

As far as modern-style social ballroom dancing goes, the biggest dance parties seem to be at the Starlite Ballroom. See http://www.starlitedanceclub.com/

A number of parties either take place in the various dance studios or are at least advertised there. See http://www.usabda-norcal.org/links.html#studios for a partial list of studios in the Bay Area.

Hope this helps!