Customizable chairs are awesome. When the customization involves picking up a sledgehammer and smashing the furniture into your desired shape, it enters the realm of genius. Not that the Do Hit Chair looks like anything I'd want to wish on my living room, but the thing looks hella fun.
Half-home fixture and half-concept art, the "furniture" is actually just a large stainless steel box that measures 40 x 28 x 30 inches. It's only 1.24mm thick, though, so you can pound it hard from all sides to turn it into an unrecognizable mass of deformed crap. That resulting heap of junk is what you're supposed to use as a chair.
The Do Hit Chair comes with its own long-handled, wide-headed sledgehammer that you can use to mold it into your desired shape. That is, if your desired shape for a seating equipment looks like it just came from the heap at the friendly, neighborhood scrap yard.
Designed by Marijn van der Poll, it's quite a novel idea. The implementation, however, looks ridiculously unusable as a home furniture (seriously, even the designer on the video below couldn't turn it into anything that's even remotely comfortable). If you're in the market for an alternative to a punching bag for stress relief, though, it could probably work.
Apart from the exercise you're going to get pounding the Do Hit Chair with a sledgehammer, you should also get an additional workout from moving it around the house till you find a suitable spot where it won't be out of place (damn thing weighs 37.5 kilos). Personally, I suggest putting it right next to the garbage can outside, but that's just me.
[More at Droog]