So-called 'blimp' cases are designed to greatly reduce the sound of a camera's shutter, making it safe to take record shots during filming for TV and movies. Typically, commercial blimp cases cost upwards of $1000, but pro photographer Dan Tabár made his own using a Pelican case, some ABS pipe fittings, a wireless shutter release, and other simple parts sourced at a hardware store, for around $80. 

The materials that Tabár used to create his homemade blimp case are pretty inexpensive, and mostly sourced from local photo and hardware stores. 

As well as soundproofing his Nikon D800, Tabar's case also renders the camera waterproof. By building space inside for a wireless trigger, Tabar trips the camera's shutter externally, removing the need to drill a hole in the case for a remote release, or shutter doubler. Images can be composed and reviewed through a window in the rear of the case made of Lexan - a tough polycarbonate resin. Operation is full-auto though - unlike some dedicated weaterproof casings (and lightweight fabric blimp cases) there's no way of adjusting exposure settings once the camera is sealed inside Tabár's DIY case. 

Tabár printed a life-size picture of his D800 to act as a guide when fitting out the inside of the Pelican case to accept the real camera.  Tabár modified his sound blimp with Lexan, rather than glass for greater durability.

You can read about Tabár's plan and execution building his waterproof sound blimp here and here. Here's a demonstration of how well it muffles the sound of his Nikon D800's shutter.

DIY sound blimp case demonstration