You might also be interested in this:
http://www.bookcrossing.com/forum/6/6315198/52
Some people on the bookcrossing forums organise a "readathon" to try to clear some books off their TBR piles. The goal is to attempt to read for 24 hours during a chosen week (of course no need to read for 24 hours in a row). Doing it as a group sounds like fun!