I enjoy visiting festivals and special gatherings, especially in smaller cities and towns (where the crowds aren't so overwhelming). Fodors recently featured a listing of some of their favorites in the USA, many of which I'd not heard of before. It's worth a look at this link.
Are there any others you know of that are worthwhile? Perhaps from your hometown? I can think of 2 from my former home city of Spokane. One of them is hoopfest, and the other is the Bloomsday Walk/run. Oh, I almost forgot Pigout in the Park!