Last year it was deep-fried butter. The year before that, chocolate-covered bacon. This year the food buzz at the is likely to be deep-fried Kool-Aid.
I had the chance to try out a number of fair foods at the San Diego County Fair's media night. I thought the deep-fried Kool-Aid was great! It's basically like a warm doughnut hole with a gooey red center. I also tried the deep-fried brownie and took a bite of a corndog covered in chocolate. The brownie was delicious, and the corndog was OK. Basically, anything deep-fried and dipped in chocolate will taste good.
Also available deep-fried: corn on the cob and ribs!
The giant cinnamon rolls still remain a good choice for indulgence, and my overall favorite thing I tried was a veggie kabob (not fried but heavily seasoned with massive amounts of sodium, I'm guessing).