We are exceptionally lucky to have the Great American Beer Festival in Colorado. The Denver fest is easily the biggest and best of its kind.
The Denver Post has a good preview here. Although, if I were going, I certainly wouldn't waste my time on Fat Tire, as the author suggests. There's way too many good beers at GABF to bother with anything that can be found at every neighborhood liquor store.
The festival will be held Sept. 24-26. Tickets already have sold out.