Promote your open house, camp fairs and other events for free
1. Facebook Events. According to Facebook, "you can organize gatherings and parties with your friends, as well as let people in your community know about upcoming events. The Events applications page displays your upcoming events, any invitations you have pending, and links to your own events."
2. CalTweet.com: "Find Events via Twitter, Facebook, Myspace, Email & other social media sites right from Caltweet."
For more options like these, type "list your event" or "advertise your event" into Google. Lots of stuff will come up. For example, you'll be able to post your open house in online (and offline) community calendars and all that. And you can do it for free.
The only thing to remember is, some sites (and newspapers and magazines) require several weeks advance notice to get your event listed on time. So don't delay. Start listing your open houses and promotional events today.