LOL this seems to be a really common question, so I might make a thread on it. xD
You can buy sponges to cover your inflow, or block your outflow with a sponge. You could even purchase some drifter plants (preferably silk so they don't blow all over the place). Don't use a sponge that you wash stuff with. This is a different type of sponge. If you're going to PetSmart, then I would suggest Fluval's. Of course, you'll have to cut it to size. It just slides right over the intake. I'd start with that and see where it goes from there.
http://www.petsmart.com/product/inde...AvailInUS%2FNo