The Burning Crusade: Dark Portal opening event?

There has been a lot of speculation that there will be an opening event but no one has any real evidence of what it will be. The only thing we do know is that there will be one. Discussion on the official forums has sparked a little interest and discussion on the matter, gathering a blue response:

Drysc says,

"Everything in life is a learning process, and we have learned a lot from every in-game event we have done as to how they can be improved. I'm not going to give anything away, but the player 'clumping' that you have concerns with is something we're specifically attempting to avoid. The re-opening of the dark portal is an event that will change Azeroth as we currently know it, and it's only fitting that the tremble of such an event is felt throughout the world. It's still likely that players will group up at the portal, but the event we're planning won't encourage it as the AQ event did."

So what kind of event could it be that wouldn't encourage all of us to mob the portal? There's not been any hint of what the event might be while I've been online in the beta, so I'm left being really curious. Will it be something like the Scourge invasion? Will there be mini-portals?

What do you think they will do for the portal opening?

[Thanks to Chris McDonnald for the submission!]