Age group(s) for which this technique is helpful:
Elementary School

Primarily used to improve behavior:
At Home

Instructions for using this technique:
When my daughter breaks one of the house rules that we've had forever and then tells me that she 'forgot', she has to write sentences 100 times, such as "I will not play with the cats in the morning". She has to finish them that night. Every night that it's late, she has to do another 50. She is just realizing that it taking away her free time and she is slowly shaping up.

Other information parents should consider before using this technique:
Be firm....if you say something, do it.