Squeak Etoys is a "media authoring tool"-- software that you can download to your computer
and then use to create your own media. You can write out your project and share it with others.
Etoys runs on any Mac or Windows machine, as well as on the OLPC XO machine.
It is free.
Find out about Etoys.
Text of this guide (for searching): Script Tile: Forward by 5, a Tile That Makes an Object Move.
Open Supplies and click on an Ellipse.
Open a Viewer for the Ellipse with its halo's cyan eye. Click on the Ellipse forward by 5 tile in your Viewer and drop it in the world. Your tile should look like this now. Click the green clock to start and stop the script.
Try other positive and then negative numbers too.