yoyos

The yo-yo is a pocket disk toy consisting of a length of string knotted at one end to a flat spool. It is played by holding the free end of the string (usually by inserting one finger in a slip knot) and pulling at it so as to cause the spool to turn whilst suspended in mid-air, either taking up or releasing the string. First made popular in the 1920s, yo-yoing is still very much enjoyed by both children and adults, though it was originally made as an adult's play toy. by wikepedia