GameMaker is a program designed to help people make their own games.
Here are some links:
Game Maker Page - http://www.yoyogames.com/make
Student made video on getting started - http://www.youtube.com/watch?v=dYAK6S4HcH0
Resources for High School students using Game Maker - http://www.mindtools.tased.edu.au/gamemaker/default.htm