Ted Drewes rocks.
The fact is that I can't order an "All Shook Up," without singing "uh huh huh" and raising my lip to look like Elvis. (An All Shook Up is a banana and Reese's peanut butter cup concrete at Ted Drewes and it is by far my favorite), and for some reason that makes me really happy. I think Ted Drewes brings out the kid in all of us, and while, IMHO, there are better frozen treats to be had (shaved ice over ice cream in Kauai, Hawaii), you'd be hard pressed to find a better quick dessert experience in St. Louis.
I have wowed many a friend from out of town with the Ted Drewes phenomenon. As one poster correctly pointed out, the hype gets pretty big, but if you simply don't pump it up too big and instead let your guest discover the magic on his or her own it will never failed to please.