Workshop Photography

I have been asked to do a workshop photography for team-building purposes for enterprises.
Needless to say: this is very fascinating.

However, it is not quite easy to come up with a theme or to figure out how to start and end such a session.

First of all I think we should keep in mind the main aim of such a team-building day, namely to incite the team-spirit. A strong team is able to realize strong things. At the end of this team-building, the employees should feel a kind of bond.
I already know that this bond will have to be shown in the pictures they have taken, and the collage (or something else) which will be made by them, or by me with their directions.

What I also know, is that is has to be FUN. They have to think out of the box, create and laugh a lot.

And last but not least, there is the time-issue. How much can I do in 2 or 3 hours and will I succeed to stay within this limit?

So at the moment, I have to thoroughly think this through. Any tips will be deeply appreciated.

Think, think, think...