Consumerist

Ask Martha: [www.marthastewart.com]

My sophomore year in college we had an unscrupulous roommate who somehow stole an entire grocery cart full of carpet samples (he didn't know either, just wheeled it home drunk as anything one night). Eventually we found an excellent collegiate use for them: the Disposa-Floor!
Whenever we threw a party we'd lay down the samples covering our apartment carpet. Then spills and the like were easily and instantly handled by simply tossing the affected carpet sections and putting down new ones. Probably saved us a few hundred bucks in professional carpet cleaning bills. ;)

I did the DIY cat scratch post, and the cats love it. You just have to watch out, because then they associate that carpet with things that are scratchable. It might work better to use your neighbor's carpet remnants for that one.

@Underpants Gnome: Our apartment happens to have carpet that exactly matches the carpet on commercial scratching posts. (I think it's just the cheapest carpet there is -- every apartment I've lived in has had the same kind.) The cat has, to my surprise, gradually caught on that carpet on vertical surfaces is OK to scratch, but carpet on horizontal surfaces means getting hit with the spray bottle.

Um...how about runners for high-traffic areas?