Another option for our leftover roast beef is this Open-Face Roast Beef Sandwich. The sauce is a mix of horseradish and sour cream; it is so delicious. I used to turn my nose up at horseradish but I think it's definitely the sort of thing you gain a taste for with age.
This is a very simple meal, but it's very tasty. Maybe the enjoyment is amped up because I didn't have to work very hard for this one.