I just remembered that I had not included my own answer to the question.
I would divvy it up into piles of $200,000 each so I could sustain my work for five years. I would identify a smallish district (10-20 schools) and begin a long-term, community-wide campaign to engage parents as customers of public education.
For some reason, talking about public education in anything less than uncritical terms has become taboo - which is ridiculous. It's our money and our kids - they exist to serve their communities.
Remind parents that they have an eminent right to demand accountability, performance, and responsiveness. With a five-year funded effort, you should be able to influence public opinion and ultimately the local elections process. Once you have a community and school board full of people with a consumer mentality, you'll see the public start to take the reins again of this public service.
Verrrry interesting.
Brett's right; speaking ill of one's school is taboo, or close to. The idea of putting some resources into engaging parents as customers rather than fundraisers and loyal fans -- yup. I'm on board for that one.