This is a great, easy introduction to Gamemaker and object-oriented programming.
I've done this class with kids as young as 7 or 8, and it's always been fun. Kids see results very quickly.
You have two options -- Option #1 is to download the "guts" of a CD -- unzip the files and burn to a CD. The CD will auto-run with a menu that will run Gamemaker, with all the files you need for the class, and have the lesson plan available at the click of a button. Everything on the CD is free, so you can make as many copies as you like.
Option #2 - follow the links to download Gamemaker, if you don't already have it installed, install it on your computers, then download and unzip the files for this class, including the sample game files and the lesson plan. Put the game files where the students can find them.