I bought this activity cube at a yard sale for $1. One of the sides were missing an important piece so the owner let it go for close to nothing.
I unscrewed all the sides, cut down a 2x2 beam into four pegs for each side and suspended them on the wall. I used L brackets to support the pegs. They are out of the way and the kids still play with them all the time. Best part is, you can switch them out with other activities cubes of like size!