Ok, may sound a bit unhealthy but this is for those times you describe, so here goes.
I always keep canned chicken or canned beef on the pantry shelf, frozen mixed veges in the freezer and potatoes in our house are a stable.
Open a can of beef, cut open a bag and wash some taters, put it all in a skillet and call it stew.
For the chicken, add some frozen broccli, pasta of some sort, maybe a can of creamed soup and a little cheese if you have it and wallah~~~
DINNER IS SERVED--BON APPETIT'