There is a children (6th, 7th and 8th standard) yoga camp going on here in the last week of this month and I have been asked to conduct a 3 hour workshop on RC planes. I feel 3 hour is too short for RC plane related workshop and may not be appropriate for the age of children attending. Instead I could conduct a workshop on chuck gliders, where children will be divided into groups and each group will be building their own chuck glider. In the end, each group will fly their chuck glider and whomsoever's stays longer in the air, wins.

Any other suggestions would be greatly appreciated.

Vishalrao
good idea.
I think VC sir is master for chuck gliders so you can take help from them.

Thank you Shailesh! I'll contact VC sir.

You should absolutely try this. Many designs (although fairly similar).

http://en.wikipedia.org/wiki/Walkalong_glider

http://www.instructables.com/id/Indoor-Paper-Airplane-Walkalong-Glider/

Whoever does this first and walks (with the glider floating) over a distance (say 100 feet) should be the winnder.

I am sure you are not gonna miss half n hour telling them basics of RC airplane as well.
Further you can have a demo flight of your Funcub or easystar.

If they taste RC flight, i am damn sure a few will get addicted to it 

Thank you Anwar sir! That's absolutely amazing. I'm going to try it immediately. I think this would make an exciting finish for the workshop.

Thanks Abhay! Yes, I would be including half hour on airplane basics. A demo flight is indeed planned at the end of the camp. But I'm planning to do that with a scratch built of my own. An EasyStar/Funcub would definitely spoil their building skills