As everyone knows, the Plunger Uncertainty Principle dictates that you can know where your plunger is, or you can need a plunger, but never both at the same time. If your toilet is clogged and you can't find your plunger, place a plastic bag over a mop to get the job done.
As ICanDoThatPlumbing demonstrates above, many minor clogs can be cleared up with a plastic bag-covered mop. Just place a plastic bag (or a few) over the head of a mop and place it fully inside the drain. While it's not quite as effective at creating a vacuum as a plunger, it can still do a decent job of clearing up minor blockages.