Poole have a Twitter feed which also gives race by race updates of home and away Poole meetings. They also encourage fans into the pits up to 30 minutes before start time (I know some other clubs also encourage this), but these are both things for existing fans!!!
To attract new fans - no matter what their age - it has to be about entertainment, excitement, controversy(?!) and value for money (ie cheaper than it is at the moment) - but that will mean a major reduction in costs to riders, which in turn would mean lower wages and savings that can be passed on to fans, either by cheaper admission and/or extra attractions !!
The thing with 'other attractions' is that it would need to be a range of different things aimed at the variable age groups - one man's marching band is another man's torture!!