Last year my wife brought some clay home and we all had a go at building something. I chose to make a Raspberry Pi case. Mine hadn't arrived by then so I worked from the schematic on the website. Clay shrinks a bit when it's fired, so I made it 10% bigger. Unfortunately when my Pi arrived it didn't fit in the case as one of the side pieces leans a bit far over and prevents it going down in. One day I'll get my drill out and see if I can (carefully) cut away a bit at the clay.
Update: the clay was too hard to cut. Also here's a much better ceramic case http://www.shapeways.com/model/1219737/pi-dish.html?li=shortUrl