The New York Times has a fascinating story about a house with a mysterious riddle. Specifically, a house on Fifth Avenue where the architect threw in an alternate reality game for free. Without telling his clients...

They are living in a typical habitat for the sort of New Yorkers they appear to be: an enormous '20s-era co-op with Central Park views (once part of a triplex built for the philanthropist Marjorie Merriweather Post), gutted to its steel beams and refitted with luxurious flourishes like 16th-century Belgian mantelpieces and custom furniture made from exotic woods with unpronounceable names.

But some of that furniture and some of those walls conceal secrets — messages, games and treasures — that make up a Rube Goldberg maze of systems and contraptions conceived by a young architectural designer named Eric Clough, whose ideas about space and domestic living derive more from Buckminster Fuller than Peter Marino.

The apartment even comes with its own book, part of which is a fictional narrative that recalls "The Da Vinci Code" (without the funky religion or buckets of blood) and "From the Mixed-Up Files of Mrs. Basil E. Frankweiler," the children's classic by E. L. Konigsburg about a brother and a sister who run away to the Metropolitan Museum of Art and discover — and solve — a mystery surrounding a Renaissance sculpture.

What a fun idea. Be sure to look at the slideshow.