You may also use Open WorldCat, either by simply incorporating links to publicly accessible records or by enrolling in Open WorldCat's Partner Access program. Contact us if you wish to discuss enrolling in this program for the purposes of this contest.
Your mission is to write a program that does something interesting and innovative with the WorldCat data using at least one of the OCLC-provided services. You must submit a working prototype.
Part of your job is to convince us of why your program is interesting and why it will help libraries and/or library users; other than that, you're free to implement whatever strikes your fancy.
If you have ideas, but haven't taken the time to bring them to fruition, this might give you the incentive you need.
(FYI - I work for an OCLC network.)