Activity:  Begin by putting a tee in the green, and another tee 1 foot behind it.  Pace off 10 feet, and drop 5 balls on the green.  Stroke the 5 balls past the 1^st tee, and short of the 2^nd tee.  Gradually move further away.  Use the ratio of 10 to 1 for the distance.  Example: a 20 foot putt has a 2 foot circle, a 40 foot putt has a 4 foot circle, etc.

Completion:  A success is 4 of 5 balls in the circle.  After succeeding at a distance, move further away.  This is a great competitive game with a friend.

Variation:  When you get better, reduce the ratio.  20 foot putt has an 18" circle, etc.

Commentary:  When I coached Tiger Woods at Stanford, he wanted to perfect his ability to die the longer putts at the hole.  This was a drill we used to help accomplish this goal.