Free wheel dyno if get your name on the list. Tons of vendors. I bought my Dana 60 from a guy I met there. There is always a burnout contest as well. Lots of crappy food to eat, too!
Last year was bad because of rain. On a good weather weekend there will be 1500 plus cars. It is billed as the biggest gathering of Mopars in the midwest. When they had the Challenger run, it was incredible how many cars were there.
It goes usually until 3:00, I believe, but the vendors pack up and are leaving at noon. This year it will be May 31st - June 1st. I will be going as will my brother if the weather holds. I plan on getting on that dyno this year.