From HouseholdHacker:
In this project we will show you how to take those old Legos you have laying around and turn them into something unique and useful! We will be creating a hidden drawer inside a lego block that will not draw suspicion. By attaching some magnets to our final project we can create a safe only accessible if you know where the internal magnet is.
This is a project we have been looking to make for awhile so we hope you enjoy it! Legos are awesome and the possibilities for this are endless!