Congratulations Idoone! MEIS, for all I've heard, is an outstanding program!
Was the email notifying you of acceptance an official one including an offer? An email from your POI or DGS?
I've heard nothing, and like Conmel, I'm waiting on a response regarding the Joint MEIS/History Ph.D.. Perhaps now that you've crossed the Rubicon, Idoone, you can be the one to ask whether all accepted students (including those applying for the joint Ph.D.) have already been notified? Just tell them you want to know for the sake of your friends up on the Grad Cafe.
Again, congrats!