I'd say this qualifies as pretty clever: Architect Secretly Builds Epic Scavenger Hunt into NYC Apartment.Eric Clough isn't your typical architectural designer. Sure, he'll design you a fine den or kitchen, but he's clearly got a creative streak that goes much deeper than that. That's why, when given the opportunity, he secretly built an incredible scavenger hunt into a $8.5-million, 4,200-square-foot Park Avenue apartment that included ciphers, riddles, poems and a lot of hidden doors and compartments.
(Hat tip to Jordan)
Update: NY Times article here - a bit more backstory. Thanks J.