Lentils with old vegetables from the back of the crisper drawer make a delicious, filling, and inexpensive meal.
Pre-cooked lentils keep in the refrigerator for months (try these: http://www.melissas.com/Steamed-Lentils-p/28.htm). With cooked, the dish can be prepared in a few minutes. Dried lentils are very inexpensive (feeding 8-10 people for $1.50) and keep even longer, but need to be cooked for 30 to 45 minutes.
Clean lentils to remove any stones. Mix lentils in 6-8 cups of water or broth. Bring to a boil, then reduce and simmer for 30-45 minutes.
Chop carrots, celery and onion (or any other handy veggies). Mix vegetables with warm lentils and vinaigrette.
Serve warm or cold.