Hosting and marketing a social event is actually pretty similar to planning a live music event in some ways. In this case, though, the "fans" are of your company or of the venue or activity where you're hosting the event. Dig into your customer's demographics, the demographics of the venue where you'll be hosting the event, and the demographics of the people in the area of the venue. What do they like to do? Where do they hang out? Partner with one or more of those places. Seek out your audience and market to them where they are, rather than trying to attract them to you. Give me a call if you get stuck and need help, of if you just need to brainstorm ideas. I've been involved with some pretty interesting promotions for live events!