J.C. Hiatt put together the conference MagnoliaJS in the town of Jackson, Missouri to help his community and combat the growing problem of brain drain in his state.
MagnoliaJS is not only for his community, but it was put together with the help of it too. J.C. put it together, publically by using Github issues, blogging, and posting about it on Twitter. The community responds well when you are genuine and trying to do something good, and bringing them in and giving them a sense of ownership is what J.C. attributes as the single most significant contributor to the conference's success.
If you have the opportunity to do something like this for your city, go for it. Bring in as many people as possible, contact your city officials, plan it publically. Technology can have a significant positive impact on a community!