Just to add more details about my call to MIT yesterday...
I called about 4:45 EST, after all the decisions from yesterday had been posted. I asked the secretary if all acceptances had been released. I was transferred to someone else, who put me on hold for a minute or two after I repeated the question. When she came back, she said that they'd be done today or tomorrow; they're not sure what their schedule is yet. As of yesterday, I thought there was a good chance that they weren't done, based on what the person I spoke with said. I still think there's a good chance there will be some calls today, but there are 4 or 5 acceptances posted already (I said 4 or 5 because I'm not sure if the person who got a missed call later added the details of their acceptance). If you don't hear by the end of the day, you probably weren't accepted... but there's still wait list.
The suspense is killing me too.