Actually it's officially Aircel official offer.. If you aircel customer might be know that aircel providing His users gift in morning Time 6 AM to 9 AM. Means in this time duration you can talk unlimited any aircel Numbers Free.
So for using this offer You have to activate it First..
So just dial from Your mobile Below USSD..

First Dial USD *121*06#

Then Dial *121*09#
Now You receive successfull Msg.

Now Enjoy Unlimited calling..

This trick is cheaked in UP East.Cheak ur states where aircel service available.