Get a large piece of card and draw a picture (as large as you can) of whatever corresponds with your theme (or something that appeals to your child) - dalek, monsters, fairy, dinosaur, pirate etc - Next make a “tail” to pin on it. For a monster make a warty nose, for a fairy make wings or a wand, for daleks use a stun gun, make a dinosaur horn, a pirates’ wooden leg - or his eye patch.  Specify exactly where it should go with a dot to avoid dispute later.

Blindfold your guests - spinning them around three times if you like. Hand them the tail and ask them to stick it in the most appropriate place. Use blu tac to stick your “tail” to the page and a felt tip pen to make a note of where each party guest places it. Initial each attempt. The closest to the spot wins.