Google Calendar has a new interface, which is now the default look for all Google Apps domains. This brings Calendar more in line with the other Google tools, in order to give users a more consistent experience as they go from one tool to another.
Some of the new features are:
1) Quick Add - has been moved under the CREATE Button
2) Calendars listed under MY CALENDAR and OTHER CALENDARS no longer have colored backgrounds. The arrows next to the names of the calendars will have colors.
3) The calendars listed in the left sidebar are collapsed (by default). They can be expanded by clicking on the small gray arrows.
4) PRINT and REFRESH buttons are now icons, not links.
5) Release Track: Rapid and Scheduled