At any one time, we usually have at least 8 or 9 cups in various locations around the house. As you could guess, we don't have that many people actually living here. Inexplicably, our dirty cups multiply like bunnies.
So this weekend, I instituted a new rule in our house. If you're drinking something, you need to have your own personal rubber band on the cup in your hands. If you can't find your rubber band, it's time to search the house for it and wash the cup it's attached to (or better yet, re-use it) before getting anything clean out of the cupboard.
So far, it has worked like a charm.
I, honestly, can't believe that I'm the first person to think of this. And I doubt I even need to describe it. See the stuff in the picture. Get it and make them. Though, I guess I should mention that rubber bands are hard on the permanent markers. Keep a scratch piece of paper nearby to occasionally doodle on, which wipes off the rubber band build up.
And this method will help cut back on the transfer of cooties, too. If that's an issue at your house.