catching and releasing flies. It's all about the approach...
Squashing flies in mid air. If a fly lands on your cake, clap about six inches above the cake. The fly has a reflex action to danger which involves a jump, right in between your closing hands.
I demonstrated this on a CTC ride to Faringdon a few years ago. It works brilliantly but the downside is that you then have to go and wash fly guts off your palms.
I suspect this would be banned as on a par with shooting live pigeons from the traps.