St. Paul (MN) has a great science museum with a lot of good summer classes, and they often have classes during the year as well (honestly, as we only have used the summer programs, I don't pay as much attention to the ones during the year). I am not sure they have something weekly that you can just sign up for, but there are a lot of offerings.
I'm not sure about Chinese, but I am guessing in a metropolitan area this big there are programs (I know of a good Japanese program, but Chinese just isn't on my radar...).
