Now gmail got fresh look and its not available to everyone. Its really very fun to work with new gmail. Its available only for who have an inbox by gmail invitation. Remember it works only in Chrome browser. Check the image below how new gmail inbox look!
HOW TO GET AN INVITATION ?
DO YOU HAVE INBOX BY GMAIL? THEN HOW TO SEND INVITATION TO YOUR FRIENDS?
After you get Inbox, you can send invites to your friends. You'll get more invites periodically, so if you don't have invites now, you'll get some soon.