I was going to say "do anything but eat it" but on second thought, you can soak each slice in milk, wrap it up in approximately 1/4 pound of seasoned (salt, pepper, garlic powder, and diced onion) ground beef, shape into oval patties, fry, grill, or bake them, and pour mushroom gravy over them. This is commonly referred to as Salisbury steak. I serve mine with mashed potatoes and whole kernel corn or peas for a delicious, although carb heavy, Sunday dinner.
ETA: Now that I have mentioned it, I haven't made Salisbury steak in ages, so I think I'll make it this week-end, with enough left over for at least a couple of lunches during the week. THANKS FOR THE NUDGE!