Sara, over at Learning the Frugal Life, has an Eat from the Pantry challenge going on this month. I just learned about it but I'm joining and will plan our meals around what we already have for the rest of this month. Fortunately, the MPM entry for this week already uses things we have so I don't need to switch gears there.
Eating from the pantry is something we try to do on a regular basis. We buy virtually all of our food on sale and buy a good quantity so rotation of foodstuffs is a necessity. Of course, that means that when something is nearing its 'end of life' stage, we consume it! But that also means we don't spend money for food items we already have unless we need to stock up on them.
My goal for the remainder of this month is to buy only milk, eggs, and fresh produce. I don't know that I'll make it since the stockpile mentality causes me to become a whirling dervish when I see certain things on sale but I'll be happy if I just cut waaaaay back on what I buy.
If you'd like to cut your grocery bill, set a goal for what's left of this month and join the challenge!