a couple of times in the summer. Cook the roast (we use bottom round) to 120 degrees then let it cool. About two hours before service I slice it (5 on my slicer, a little thicker than sandwich thick) and let it steep in gravy. This year it took two 8 lb bags of potatoes (mashed) to feed the herd. We did two roasts this year, one in the gravy and one sliced for sandwiches (around 3.5).
Edit, we started this last year, for the previous 53 years of my life it was always turkey. This was one of the hardest traditions I've had too "move on" from, but the roast made it a bit easier.