There are probably easier ways to hide your valuables in your home than to build a secret compartment into a table. Nonetheless, this safe built into a chess table is a clever design -- not just because it's well hidden, but it requires you play the right moves before it unlocks.
The video above walks you through how the whole thing was made, and the switching system that uses magnets on the bottom of the chess pieces to track movement and position. You can't just put the pieces in the right place, you have to move them to their required destination, in order, before the lock will open and you can get at the stuff inside. It takes nine chess moves before it will open.
One of the best things about the project is that while it's fairly intricate, Instructables user oldsouliving did it largely with materials he already had lying around. If you open the door to the chess table, you'll see a bunch of books and other items, but behind a locked false back, he hides the real goods. Hit the link below to see the whole process from start to finish.
Secret Compartment in Chess Table with 9 Move Combo Key [Instructables]