If you have multiple kits and laptops, and can have several stations set up each with a person who knows what they are doing, the kids can just experiment with the programming, with a robot that is already built.  They can just play with it, learn how to go in a straight line, make a turn, follow a black line, etc.

I have also used the following exercise several times before.  I started off with this as a demonstration at the beginning of the session.  If you do it in a large group, you can either pair everyone up, or start with just two volunteers to demonstrate, and then have them partner up and try it.  Have the first volunteer put on a blindfold and then ask the second volunteer to instruct the first to do a simple task (like go pick up that cup on the table).  It is eye opening that they can't just tell the person to go get the cup.  They have to break it down into steps, be very specific, and then adjust when they over/under shoot for the target.  This is just such a great demonstration of what programming is like.  It helps them understand that they have to tell the robot to do each step to accomplish a task, and that it's not all that easy at first.

Good luck!

Sonya Shaver in Harrisonburg