When I came to Google four years ago, a small group of engineers was putting the finishing touches on a calendar application. A few of us started using it, and I remember thinking, "Wow! It's so fresh and shiny and new!"
But over time the shiny new Calendar started to feel a little bit old, a little out of step with other Google Apps. So we rolled up our sleeves and we tweaked the layout, we twiddled the colors and we tuned the text...and this week we're pleased to show off a fresh new look for Google Calendar.
If you use Tasks in Calendar, you'll discover another change: we've removed the old Tasks link. Now to turn Tasks on and off, just click the Tasks calendar in your calendar list. If you only want to see tasks with due dates — the ones above your calendar — you can hide the task list by clicking the tall blue bar that separates the calendar from the task list.
Source : http://gmailblog.blogspot.com/2010/05/new-look-for-google-calendar.html