One can only sit on the DRM Chair eight times before it collapses. Thibault Brevet and friends created it in 48 hours for The Deconstruction hackathon.
A small sensor detects when someone sits and decrements a counter. Every time someone sits up, the chair knocks a number of time to signal how many uses are left. When reaching zero, the self-destruct system is turned on and the structural joints of the chair are melted.
(Thanks, Jason Tester!)