You should contact the multi-cultural center in Sioux Falls for some of your questions, if nobody has insight otherwise:
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The night life is what you make of it. Plenty of nightclubs, comedy clubs, movie theaters, bowling. Alot of the churches have stuff for adult singles, young and old (google churches/sioux falls.. there's alot!)
Often stuff going on downtown, at the parks, at the arena. I've noticed more in the summer.
For hair care, I don't know of any right off hand. Contact Stewarts School or Black Hills Beauty School in Sioux Falls, they may do services or have good leads.
Hope you move here and love it