If you are into antique, collectable, various odds and ends, you should come to Oronoco Gold Rush.
Oronoco is a small town north of Rochester, MN with the population of around 800. On the 3rd Weekend of August, the population swells to around 15,000 to 20,000 for the Gold Rush Days. They advertise it as a Saturday/Sunday event, but i'm from Oronoco and can promise you that most of the stalls are operating on Friday as well.
It's a very fun place to look around. Every year there is a man selling golf balls very cheap, one sells collectable drinking glasses, etc etc. Name the antique you can find it there.
Recently the information booth started creating a database of all the vendors, so if you are looking for something in particular, they can tell you where to find it.