It all started with a Benno TV holder furniture http://www.ikea.com/it/it/catalog/products/50203104
We wanted to enclose out HTPC into that cheap furniture, making it nice looking.
Step 1: Hinges and a Hole
The first thing you have to do is buy a wooden panel which will be the door to hide the PC.
Screw some hinges on it and make a hole to hold the PC power button.
Step 2: Cover the Door
Cover the door with some nice looking fabric.
IKEA have many kind of them, fix that to the panel using a professional stapler.
Insert the button in its hole.
We used GULLVI: http://www.ikea.com/it/it/catalog/products/20208612/
Step 3: Prepare for the Mobo
Place some little srew holder right into the furniture wood.
The ones we used were into the PC case we had before this idea.
We put some glue to be sure they were stable.
Step 4: Fix Mobo
Place the motherboard over the holders and screws it.
It should be very stable and fix.
You can see a picture of the rear of the furniture, we strongly encourage you to fix wires as we done.
Step 5: Add the Door to Furniture
Screw the door hinges directly on the bottom of the furniture.
To make the door closeable, screw some magnets below the middle plan of the furniture, and some iron plates in corrispondence of them directly on the wooden panel.
NOTE: you have to solder the PC power button if you want to swith it on!
Step 6: Close and Enjoy
Now you can close the door and enjoy your media center PC!