It was wonderful!! I followed the recipe from foodnetwork but I did start it out at a higher temp for a bit and then lowered it (because my sister told me that's what she has done). I went with 450 for 15 min. to sear it and then turned it down to 325. I believe that recipe was for medium-rare at an internal temp of 125 but my thermometer said 130 was medium-rare. I didn't want it that rare so I went to about 135. I knew nobody that would be eating it would want it rare. And one of those sites you guys gave me said to set it out ahead of time so it was more room temp at cooking time. I did that as well, but had no idea how long it would take so I may not have had it out long enough to get exactly room temp.

Anyway it was a great x-mas eve dinner. Only way it could have been better was for my brother to be there. It was our first Christmas without him.

I've heard of cooking other meats in a bag and they've turned out wonderful, but not prime rib. I don't think you can get that outer crust (hate to call it crust...sounds bad) cooking it in a bag.