I don't know about America, but in Australia it was "meat-n-3-veg" - typically lamb chops with tomato sauce (out of a bottle - what they call ketchup in the States), mashed potato, and (over-)boiled carrots and peas, seasoned in butter and salt.
Depends a lot on the region in question. A lot of traditional New England would be a lot of baked stuff such as baked beans and pies as whatnot but it would be different in other areas.