This is another way to randomly choose who will sing in order to review a song several times. Roll the cube and those children who are wearing the colors shown on top of the cube should sing. I've made a new cube with two colors showing because the group I'm now working with is quite small. No one really likes to sing alone, so I tried to use neutral colors on all sides. This maximizes the number of children singing since almost everyone wears either black, brown, white or off-white, at least in their shoes and socks!
I made this cube out of plastic canvas and yarn. I whipped the edges together and put a large bell on the inside to make the cube roll better. I could have used a large bead or stuffed the cube to make it a little heavier, but I thought a bell was just the ticket. If the cube doesn't roll effectively it might be too light in weight. Cubes need some weight to give them momentum as they roll.