I found this adventure game made for the LA public library. The game is called the Goodhue Codex. You have to solve riddles, find thinks and make your way to the rare books section. You have to register, but you do not have to give your e-mail address. You can find the game here.
Kimbooktu.com 
Just played the game, which was nice for me, because I live in L.A. and love the downtown library where it’s set. Thanks for the link!
Did it look like the library?