Downtown Sioux Falls did not disappoint - it is definitely worth your time to visit.
Most of what you can see, buy or eat is located on (or adjoins) Phillips Avenue, so that's where you want to head. Most of the shops open at 10 AM and the restaurants at 11 AM. If you get there early enough, metered street parking will be available (free on the weekends).
When you walk south on Phillips starting at about 8th street, the most distinctive feature you will immediately notice is that the entire downtown is populated with unique metal sculptures, adding interest to almost every block; these things are everywhere, and some are quite unique. For example, we found this cat from outer space.
For shopping, one store you must see is Zandbroz Variety, a unique retail offering of just about every eclectic, quirky doodad you can imagine -- and then some.
How about a David Bowie Ziggy Stardust Xmas ornament? If he won't do, there's always Ruth Bader Ginsburg.
These are just the tip of the Zandbroz Variety iceberg.
There are also several art galleries in the area worth exploring; these feature sculptures alongs with oil and water color originals as well as prints by both regional and national artists.
After you've browsed up an appetite, we highly recommend the Phillips Avenue Diner; order the Pot Roast Dip combo sandwich stuffed with onions and peppers and served on toasted sourdough.
You'll definitely enjoy the retro 1950's layout, including overstuffed booths where they'll gladly serve you a toasted s'more chocolate shake.
Finally, right across the street from the diner is Urban Archeology, one of the best small collections of artifacts and memorabilia from the last century we've ever encountered.
The DW let me purchase a 1930's AM tube radio with an Art Deco style wood case; it still works!
Now she tells me I just need to find a place to put it.