The first time I saw this happen, I was amazed. A BMX track, down on its luck was able to rebuild with a grant from the county. It went from near bankruptcy to pulling in a couple thousand per month. A second track got the same idea. They used their own money and their numbers exploded. Now a third track has fallen in line. I was lucky enough to witness and document the results of all three.
The reason that I'm writing this is that I always read about kids on BMX forums complaining that their parents won't build or rebuild a track in their community. Kids, read these stories. Print them out, show them to your parents and bring them to your local county or city commission. These are low cost / high income propositions.
I put the latest story on my blog but there are many others out there that can be used for reference. There is a 20 year old running one of these tracks. It's not as hard as you think. Good luck.