This is a super-immersive, amazing idea to get a whole community involved in a book! The Toronto Public Library held an alternate reality game to get people involved with Fahrenheit 451 - click through to read how! "Toronto Public Library Enters Alternate Reality (Gaming)" -- Library Journal
If you're feeling ambitious, an ARG (Alternate Reality Game) might be something to try. It is a way of incorporating a large variety of media into a single program (including--maybe especially--social media). This particular website is more ARG news-oriented, so I would recommend taking a look at the resources compiled for NJLA in 2011 (which will, of course, turn up in a quick Google search for "NJLA 2011 ARG").