So say that using the simple "put meat in the oven and roast at 200 for several hours" method I read about here a few days ago, what would you do to it to make it into a variety of meals over the coming week, things for lunch? Different sauces?

I have a couple of these insulated containers:
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So if I make, say, a pork tenderloin roast that's seasoned with salt, pepper, and onion; and some sort of beef roast similarly prepared, how can I use them for the week's lunches?