Alternatively, and this is mostly for the college students who are lazy, lacking in hygiene, or both, in the house, milk, whose1 expiration date has passed, but not by far, such that the smell and the color of the milk cause you to not really want to drink it outright, but masked by the taste of some children's cereal (Honey Smacks are good for this), it is reasonably palatable. Just don't tell your mom that you were drinking expired milk. She won't like that.

Oh, you want a concrete example?

Say it's October, Friday the Thirteenth2, and the expiry date on your milk was for Wednesday. Now, you could throw the milk away... but it smells ... sort of safe - and besides, you're hungry! You want to eat some cereal NOW! Go for it; I promise it won't hurt. much.

1"who's"? That's not the right posessive, at all! Can someone help me out, here? (addendum: "whose"! Thanks, deep thought)
2Hey! By Jove, it is Friday the 13th! How convenient!