Vintage Days
I go every year and love it. If you are into vintage track and vintage dirt racing, this is your place. Has a nice swapmeet going on and demo rides where you can take out the latest manufacturer's bikes for a 20 mile road test. That is where I got to ride the the KTM supermoto, the BMW sport bikes, Harley VRod, the Ducati 999 and the Agusta bikes. They take you on the back country roads and let you unwind them a bit. I had that stupid Agusta Bigmota at 100 in second gear. Whew.
Its definitely worth it. I think you can camp there if you want and there are some cheap hotels in the vicinity.