Here is my interview experience in Boston, MA.
Our appointment was for 10:30am and we got there about 20 mins earlier. Went to room E160 where they told us to to go to E170 and hand in the interview letter. The we sat and waited till we were called. I think we were one before the last to arrive. Looks like they give everyone the same appointment time, or maybe 10:30am is the last appointment time.
We were called in at 11:45am (1 hour 35 mins) after arriving. The IO was a guy with no expression on his face. He had opened the door for us so when I was walking past, I said Hi ... but there was absolutely no response. I thought we were going to have some trouble. We went in and sat down. He asked for Passport, EAD and travel docs. From USC he asked for 2 forms of ID (gave drivers license and naturalization certificate)
He asked where and when we met, when we got married. We also had our 20 months old daughter with us. So he asked each of us who the mother/father of the child is. The he asked how many times have you been to the US ? why did you stay the last time you arrived. The last arrival was only supposed to be for a week, but I was hospitalized for having bad morning sickness and couldn't go back. We had a letter from the gynecologist saying that I was unfit for travel. He asked for that letter. While all this was going on our daughter had climbed up a chair and trying to pull some of the papers that were there. He told us that we better take down. I think that distracted him, because after that, to the surprise of both of us, he said that our application is approved !!
I had brought so much documentation like birth certificates, translations, marraige certificate, joint documents and tonnes of pictures but he didn't ask for any of that. The whole interview must have been about 15 mins. He told us to go out and wait for an approval letter. We also said that we will be traveling in about 3 weeks and whether we will have the GC by that time. He said that we very likely would have it, but a week before we travel if we don't recieve it, then make an infopass appointment and come in with the approval letter and that they will then stamp the passport.
We had to then again wait for another 45 mins or so for the approval letter. It was only us and the couple who came in after us left in the whole room. We and the other couple got the approval letter around the same time.
02/03/2010 : Mailed I-130, I-485, I-131 and I-765 (and other supporting forms and documents)
02/16/2010 : Got reciept notices for all 4 of the applications (Reciept Date was 02/04/2010 on all 4 notices)
02/19/2010 : Recieved Finger Printing appointment for 3/1/2010
03/01/2010 : Did Finger Printing
03/27/2010 : IL for 4/30
04/16/2010 : updates on I-765 & I-131
04/22/2010 : Recieved Advance Parole Docs
04/26/2010 : Recieved EAD card
04/30/2010 : Interview Date, GC approved