Cans don't open so good on their own.

Fact. You really need an opener. We've come real close to forgetting the Swiss Army Knife before (to the point of riding a block from home before remembering and turning around), but always pulled it off. So today, our number was up, and with a sinking feeling, I searched the bags hoping there was something that would work. It came down to pounding the can lid with a tiny Leatherman's flathead blade and a rock to punch holes around the rim...J was SO into this procedure. Banging and tools? If he had his rathers, we'd be doing it this way everyday.