Mamut Skull, a crowdfunding project for protectors for the HTC Vive controllers. Although it seems like a great idea, the Kickstarter campaign was not successful, raising only a fraction of the modest goal. In my opinion, it was due to the lack of publicity. I myself found the project with only 18 days left, and I hadn't seen it mentioned in any other blog or news site.
In any case, the good news is that the creators found an alternative source of funds and will be producing the Mamut Skull! It will be available for preorder soon. I'll post the preorder link when it becomes available.
UPDATE: Mamut Skull now available for preorder.