(aka Memory Game)
Very good game for children of all ages for sharpening the memory! Use 20 or so different small objects and place these on a tray or table covered with a cloth. Remove the cloth and allow everybody 2 minutes (or whatever time limit you prefer) to memorise what is on the tray. At the end of the time period cover the tray with the cloth and ask all players to write down what they recall what was on the tray.
To make it a little more
Another version plays it so that after studying the items on the tray or table for a short while, one item is removed with the cloth in place and the children have to work out what has been taken when the remaining items are revealed again. Each round replace the item and remove another.