Loved it! Some very interesting factoids, like ENID being a 14A: U.S. city named for a Tennyson character. The town, by the way, is Enid, Oklahoma. The story given on the Oklahoma State Library page is that a railroad official, upon arriving, asked what the station was named. He was told "Skeleton Station," which he found unacceptable. He said that no one would want to live in a town called Skeleton, so he renamed it after a character in a book he had read on the way there, Tennyson's "Idylls of the King."
The first theme answer, too, was enlightening for us. Some say that the three-ball symbol derives from the Medici family crest, because the Medici were in control in Lombardy, when and where "pawn shop" or "Lombard" banking first originated. The Medici crest has various numbers of "balls," or, I've also heard, "pills," because "medici" in Italian, means "doctors." Another story is that the three gold balls were originally three flat coins on a table, but were made into spheres to better attract attention. Whatever the origin, we didn't even know the symbol existed!
So with a start like that, it's got to be good, right? Right. So much interesting fill! Loved the anagram/cryptic clue for EPISCOPAL (10D: Pepsi-cola mix?), and although I didn't love INONE (9D: Combined) when I wrote it in (two words, seemed a little clunky...), by the time I filled in INTWO (3D: Halved), I immediately looked again at the constructor's name. I'll be watching for you in the future, Henry Hook!
Who knew BISMARCK (39D: State capital whose site was visited by Lewis and Clark) had a C in it? (Yes, it really was named for Otto von Bismarck!) or that those multi-ball toys were called NEWTONSCRADLE? (52A: Gizmo often with five balls that demonstrates conservation of momentum and energy.) (If we embedded photos and videos into our blog posts, this one would be chock full of them!)
The only slight drawback to this grid that I can think of is the spelling of YOWZAH (44D: "Holy moly!") - both of us would leave off the H - but, well, it's no big thing.
p.s. Oh, and how 'bout 12D: Early bird? (EGG)!! So much good stuff....