Good Deed Beads, also known as Sacrifice Beads, are basically nine or eleven beads threaded on a length of cord or string in such a way that the beads stay in place when a child moves them from one end of the cord to another. The idea is that the child keeps track of his good deeds and/or sacrifices for Jesus by moving the beads from one end to the other throughout the day. If you make an eleven-bead string, it can double as a one-decade rosary. A nine-bead string doubles as a way to pray a novena.
For a complete description of how to make Good Deed Beads, check out http://kareninmommyland.blogspot.com/2010/02/good-deed-beads.html