I'm always finding out about awesome flea markets and garage sale type things after the fact. I'm starting this topic as a place where people can find out about these things BEFORE they've happened.
For instance, this weekend I missed a what I was told was a great flea market at the fairgrounds.
And I discovered driving by the fair today that there is a YMCA Garage Sale going on as we speak. I haven't been yet but those are usually pretty good. They sometimes charge you a few bucks to get in though.