These 1/2" cubes have a 3/16" hole through the center which is perpendicular to the magnetization.  The poles are located on the two opposing sides without the holes.

They are great for suspending objects and signs from a string.  They can also be used to hang a string from a metal ceiling or beam.  We have used them to hold vinyl banners.  The string can be knotted or looped through the cube to secure it.

Another application that these cubes are ideally used for is to make a Halbach Array.  When five of these cubes are arranged correctly you have one side that is very powerful while the other is very weak.  When this type arrangement of magnets is run along a track of closed copper coils they will supposedly levitate.