The Board of Education is there to ensure one thing for the town: Education! So, show them how rewarding FIRST really is. Tell them about the 8 million plus dollars in scholarships that FIRST gives out a year. Tell them about how many students have graduated from your team (and other teams) have gone onto higher education. I'm willing to bet the national average is about 90%. For example, in its nine year history, my team has had 99.2% of its high school students go on to college. No other activity even comes close to hitting those kind of numbers.
And when you are done with that, show them the robot.
