They have also started Scout, targeting people aged 18 and over. They say Build a network of creative individuals who like exploring the library just as much as you do. There are challenges, and you make and discover things. It sounds a really interesting idea, and I will be looking forward to hearing more about it. The tag line is "explore, create, share" which sounds a very good basis for any library service (as well as being a great description of research...and so many other things which happen in libraries).
And of course the Ann Arbor District Library has its summer game running as well.