For Rent Cheap, with a Catch: It's a Mattress Stuffed in a Hole in the Wall.

One night, 3 architecture students living in Brooklyn decided to stuff a mattress into a hole cut into a wall & listed it for rent. To their surprise, they had potential takers!

So Mr. Freeman posted an ad on the Web site Craigslist: "$35 — elevated mattress-sized space between rooms." He used a minimalist pitch. "Opening between hall and room available for long/short-term use, accessible by ladder, sheets and pillows not provided." The ad went up around noon, and by the end of that day, Mr. Freeman had a dozen potential takers.

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