There are quite a few Oktoberfests in Omaha and everyone plays well with another and schedules them for different weekends. Bring your stein if you have one, as nobody likes drinking out of a plastic cup if they can avoid it. Glassware will usually be on sale at these events. Family friendly.
I've always thought it would be great to get all of these together and have one huge street fair bash kind of a thing to draw in tourists, etc. However, if you're in town in late September - early October, ask your bartender which one is coming up this weekend. You'll have a good time.