Do you have some old (fruit or milk) crates? Or you just need a practical (and low budget) storage (organizing) system? Try out this brilliant woodworking idea: the crate bookshelf! You can combine the crates in any shape that fits .
Great idea for hiding guns in the house if you don't have a gun safe. Or even other items you want to keep safe! It took me a little while to understand this. The shelf unit slides behind a mirror. I thought it was a passage to a hidden room.