Visual Worship

So in little over a month I have to run two 2 hour workshops for St Albans diocesan youth service on 'Preparing and using visuals in worship.' If anyone has any idea a) what that is or b) any ideas of activities I could set and c) any resources I could pillage - I would be very appreciative! (Ben I'm hoping you've got something up your sleeve!)

Thank you very much - and don't all rush to my aid at once...