A quick concentration game you can even try at your computer!  Hold one hand in the air and point your finger forwards.  Draw a circle in the air, a dozen or so times.  Drop that hand and lift the other. Do the same thing, but this time draw a cross in the air.  Easy, isn't it?  You can probably guess what comes next.  Lift both hands and with one draw the circle and with the other the cross.  See if you can keep them both going. Now for the really hard bit - swop hands without a pause.

You can do the same thing in the drama session - get the whole group trying to do it.  If anyone says its easy, ask them to demonstrate.