Just an add-on to Garry's (Lewnics) suggestion. There's times where I've only had one or two inflatables so I make a competition out of it. Cue up some well known guitar solos from some rock tracks and get them performing one (or two) at a time doing a bit of air guitar (this has proved to work well with sons and dads too at family parties). The guitar solos in songs usually only last about 30 - 40 seconds which is ample time for them to 'do their stuff' without getting bored. Loudest applause wins.