TDiFest is a labor of love - it's work, and the more people you have to help, the better. The organizers are responsible for planning the registration all the way through to the sunday night awards banquet. Events are planned for Sat and Sun with some 'free' time thrown in for sightseeing, etc. Activities can also be planned to 'guide' out of towners such as brewery tours or other tourist-y things.
Generally the Fest has been more about connecting with other forum members than with your car (show and shine and chipping are the usual exceptions!) A lot of people travel long distances to attend and don't want to tear apart their car before a 1000mi return trip! Also hotels are much more likely to host the event if you can guarantee that suspensions aren't being replaced in their parking lot!
The Fest is our way of supporting this website. It's the major source of income that pays the costs associated with running the equipment that runs the website. Think Jerry Lewis for TDiclub.com.
It's also a way to put faces to the screen names we've come to 'know' over the years. May new and lasting friendships are established at the Fests. Many times people find folks that have been in their own backyard but wouldn't have discovered that if not for the Fest. It's a social gathering rather than a 'working' GTG (at least in the past)- with the exception of our vendors.
The work comes in organizing registration, deciding fees, arranging for space, vendors, donations, figuring out where you're going to park 100+ cars, etc. It's in the details, and any of the previous organizers can give feedback - just send a pm if this thread doesn't get you enough info!