Event Management Software?

I'm thinking about doing a writing event in my area. Maybe a write-a-thon type thing or a meet local authors type thing. I don't have the budget to hire an event planner and I'm not sure I can hack it by myself. I mean, I've thrown small parties and I planned my wedding, but this is different. Have any of my readers ever used event management software? If so, how does it work? I was unaware that it even existed until today. Apparently there are companies that create this type of software and customize the software to your specific event. It sounds intriguing.