Ask HN: Need help figuring out the best ways to promote a startup event in SF...

Hi guys. I'm working on a startup crawl event in SF for next month on July 25. Here's a link: https://driveless.crowdtilt.com/sf-startup-crawl-summer-2014

So far I've already got a hacker house called the Negev and OpenDNS signed up to participate as host locations.

What are the best channels to get good people for the event and also find startups who would be interested.