Oh, yes… you can buy some, too. Autodesk and Turbosquid have partnered to start a market for Revit content (i.e. families). This joins websites with free content like RevitCity and Autodesk’s own Seek service.
There is also a contest for “early-vendors”. From their press-release:
To encourage users to publish Revit families for sale, TurboSquid is holding a Revit Contest with cash prizes up to $2500. Deadline is Jan. 31, 2009.
http://www.turbosquid.com/Revit-Contest
So what are you waiting for? Dust off your “used once and then stored” components from earlier projects and put them up…