Actually, these are pretty useful

[karadinart]

Bottle Tops - these fit over soda cans so they don't spill. Win for in the car, or just in my house with cats and kids, and as they come in different colours, you can tell which can is yours. Nice. (Just remember to rinse off the top of the can before you snap them on, one size fits all)

(a neighbor had a box of these from work and gave me a couple, I think I've seen them at the cornershop and gas station, actually have not seen these on tv.)