Find out who is most terrified of heights, someone inevitably will be!
Organise a simple sky dive session for them and claim it will be great footage for the film because they're so scared of heights.
Pre organise with the sky diving instructor who will dive with them to FAKE/ACT that the parachute is stuck and unable to open.
Film the footage via head cam, wrist cam etc etc and watch them scared stiff as they think they're failing to their death!
Theres no better humor than when people are terrified for no reason.
Alex Hardy :)