Google Calendar tests a new feature that lets you view your calendar and the calendars of your guests when you create a new event. "Sneak preview" can be enabled when you click on "create event".
"We're working a new feature that makes it easier to schedule events with guests. The new event page will include a calendar right next to your guest list, so you can see when people are free," explains Google.
"Sneak preview" helps you schedule events and it lets you find a better time for an event using drag and drop.
{ Thanks, Keith, Melle and Owen. }