Kind of wicked. I have seen pictured of those wheels in magazines before, but never really knew how they worked. After reading up on the site, the continuous spoke that feeds through the hub is kind of wild. It seems like the wheel would be slightly more flexy than a standard build though unless under really high tension. Either way, ingenious and kind of cool...
Hub is carbon fiber, spokes are kevlar and carbon.
The wheel with axle bolts and a rimstrip weighed in at ~800 grams.
The rim on there is pretty crappy too. I could shave a bunch of weight there if I were so inclined.