One thing I have found is that it helps to put a bit of work in upfront so that you have just the right ingredients in the pantry or freezer to take advantage of those little tidbits that would otherwise go to waste. Homemade stock is a great example-- with a quart of stock from the freezer, leftovers can easily become a great soup. In this case, I had a pint of homemade mole sauce, from a recipe loosely improvised from the Rick Bayless recipe published some time ago in Fine Cooking. The improvisation part mainly included throwing in any and all the different varieties of dried chile (chipotle, ancho, and a few others I can't remember) that I had accumulated in the pantry.
So, having this sauce, I was able to use the leathery, stale corn tortillas left over from taco night (I always buy too many, especially when the store has warm tortillas fresh from the factory). Also I roasted a half of a turkey this weekend-- it is hard to use that much leftover turkey before it goes bad, especially for a family of 3. Voila, a quick weeknight meal of enchiladas.
Speaking of the pantry, the kiddie palate prefers enchiladas made with canned red enchilada sauce-- so that time spent upfront could also be used to go to the store and stock the pantry.