A few things that come to mind:

The Minnesota State Fair. I've heard it's the largest state fair in the US mainly because it's the only state fair located in a large urban area (Minneapolis/St. Paul). The downside is the farm-oriented stuff (silos, combines) gets less attention than the urban-oriented stuff (bungee jumping, riding lawnmowers). But, hey, in Minnesota we're all somewhat farm- (and forest-) oriented. Actually the official website is a bore. This guy's photo collection is better.

A few others that come to mind:
The Mall of America, Bloomington, Minnesota (a suburb of Minneapolis/St. Paul)
Palace Pier, Brighton, England. (The website is not particularly descriptive, but it is wonderfully tacky in its own right.)

These I know only by reputation:
Rock City, Tennessee
Wisconsin Dells, Wisconsin
Silver Dollar City, Branson, Missouri