If this is a mass program at a school, then I immediately invite three people on stage. For the first I make some froth on the palm, for the second – a necklace of froth around the neck, the third one get ears of froth. Then I call three more, give them wands, they blow bubbles. Then I call out three more, they pull bubble trains, etc. By all means, interactivity should be present at such events.