I have seen the concert listed at noon, seven and eight and I am going with seven p.m.. I missed Johnny Rivers last year because the fair pulls this kind of time crap all the time and we were off by an hour.
link. I saw both these performers play at Slims a few years ago and they are both excellent. Not sure who is playing with them but Charlie's band was just extraordinary.
If you need to ask who either of these guys are I suggest that you don't go. Concert is free and I will buy you your first deep fried twinkie.