Kind of an a-la-carte approach to civic responsibilities? I can envision ways in which it'd work, and people would feel better about it (in general) than they do taxes. It seems like something like this would work best at a local level, which would obviously apply to the particular example we're discussing. In theory, I'd be on board with it, as long as federal programs/taxes remained. If you found a way to implement it on a larger scale, I'd be surprised/impressed.