Me and my hubby take leftovers. We just put them in a container and nuke em at work. I have done the ceasar salad thing too, it works really well.
I brought tacos today. It was a little fussy, but it tasted good. Brought a container of meat (already cooked), container of tomatoes, shells, sour cream, cheese, you get the idea. Warm up the meat and assemble.