Ask HN: Non-profit organization doing a big event. Need tech ideas.

I work for a non-profit organization that promotes citizen involvement in public issues. We are doing a big event in Washington DC in a couple of months.

I was wondering if I could get some advice from fellow hackers about technology to use during this event such webcasting, getting people to participate online (your personal experience would be even better).

Our main goal is to get a lot of people (young and old) excited about this event. What I am looking for is technology ideas that can be used via website and social media outlets to promote/generate interest.

Thanks.