The release of Google Calendar into public beta brings some powerful new ideas for website operators and the creators of web-based or desktop calendaring tools. Google has published a specification for adding a single event to your calendar. The spec uses an easy to create web tag to create a link that will add an event to your calendar. By design it is an easy way to allow website publishers to put a badge on the page that will add the event on one's Google Calendar. However it would be simple to create a small tool or modification to existing interfaces to allow patrons to easily add book due dates, appointments with librarians and library events to their calendars. It also seems certain that where Google leads in this area the other providers of online calendars are sure to follow.