We've always believed users should have open and unencumbered access to their data, and Google Calendar is no exception. Whether through iCalendar, CalDAV, or the Calendar Data API, there are a multitude of options to access Calendar from other applications. However, developers have been asking for a way to extend the Google Calendar interface itself, and we've been listening.
Today, as part of Google Calendar Labs, we're opening up Google Calendar as a gadget container.
Gadget developers will already be familiar with most of this environment, complete with features such as OpenSocial for social networking and OAuth for working with third-party services. However, for the first time we're also providing an API to control and interact with the Calendar user interface. This means that even though your gadgets are running inside a sandbox, they are first-class elements of the Calendar user experience. In fact, many of the experiments we've made available through Calendar Labs were written using the publicly available gadget API.
We hope you'll share our excitement in opening up the Google Calendar interface. To get you started, take a look at the Sidebar Gadget documentation and sample code. If you have any questions or ideas for improvement, feel free to visit the Calendar API help group and let us know!