Thermal Cookers! Boil the food over the stove. Remove once it's boiling and let it cook in the heat of the water during the day while you're out and about or traveling. Without much effort you'll have a hot cooked meal later when you're too tired to do much else. And you don't even need electricity to use it so it's great if you're boondocking
I've also used mine when vending at craft shows and everyone around me was quite envious when I pulled out my hot corned beef and potatoes for my lunch.