This video I made will show you on how to get into the Wintergrasp Chamber with your opposite faction having it, the good part about this exploit is that if your opposite faction has just won the WG game than its a good time for you to head over the spot and do what I do that way you can land on the ring above the summoning stone and gank those below you. This work with a mammoth mount and not failing like I did and missing the ring like I did.
Please and enjoy. Remember to watch in 1080p :P
YouTube - WoW Wintersgrasp Exploit.