Carnegie Mellon University Libaries 'Library Arcade'
Check out I'll Get It! and Within Range, 2 fast-paced games guaranteed to sharpen your reference and classifying skills. The games were developed by graduate students from the Entertainment Technology Center, in collaboration with the University Libraries, with support from the Buhl Foundation.
I'm not usually into games, but I found these fun (once I figured out how to play). I can see using them with students.