With most of my experience being in vendor driven events, I am wondering what everyone thought the critical success factors are for running community driven event such as a SharePoint Saturday (ie. not just a UG recurring meeting, but an actual larger concentrated event) In addition, any tips/tricks/pitfalls/etc... would be great!
If you are specifically doing a SharePoint Saturday event, Michael Lotter (@michaellotter on twitter) has a great process pretty well in place for the planning. Mark Rackley (@mrackley) has a great blog post on his site about some of the pitfalls and things to help plan an event. He pulled off the SPSOzarks event pretty much single-handedly. Here's a link to his post, it might get you started: http://sharepointhillbilly.com/archive/2009/07/23/organizing-a-sharepoint-event--what-you-need-to-know.aspx
Oh, and if you are doing a community driven event, be sure to get the local SharePoint User Groups behind it and on board EARLY in planning. They will be critical to funneling people to the event as well.