One day in fall 2002, one of our teaching physicians asked our client services team to review and update the content of a well-worn “pocket card” that was being used on his service for reference material. The card was a homemade conglomeration of other reference cards that had been cut, pasted, and photocopied into the “mother of all cards.” However, the card was inaccurate, parts had obviously been “borrowed” from other organizations, and it had been photocopied so much that parts were becoming unreadable. One thing was clear to us—inaccurate or not, this copy of the “cheat sheet” was a resource that was heavily used. And while we were chatting about the problems of updating such a card, the physician asked about publishing such data for personal digital assistants. Some days the opportunities just appear at your door.