My husband and I went to it last summer. We had planned on spending two days there but it was small enough that we were able to cover it in one day. They had a lot of info, expecially if you are planning on building or converting to solar, wind, ect. We attended a workshop on strawbale building.
The fair itself was very neat - as you walk through the field of parked vehicles you see lots of veggie cars, hybrid vehicles, and even some old VW vans.
Deffinately worth checking out. We would plan on going this year but just too much going on.