Two librarians posted a link to information on game called LemonTree. It's not so much a game as it is a reward system on the students' end and a source of data collection on the librarian's end. This is a "flavour of Librarygame(TM)" created for the University of Huddersfield (UK) by a company called Running in the Halls. You get badges and your card gets hotter the more you use it, certain IL sessions and Web instructional materials contain codes for bonus points, you also watch your online tree grow with more use.
One of the librarians will be presenting it at a conference soon and his materials will be available at: http://eprints.hud.ac.uk/11938/
This is an interesting example of gamification in libraries and I can't wait to see how it is received by students. I've also never heard of Librarygame (TM) and will have to look into it.