A lovely Saturday puzzle today with open corners and a pleasing grid. The entry and exit points in the NW and SE are a bit narrow, but it didn't impact the solve at all, as ILLUMINATI (23A: Group in many conspiracy theories) and RIVERDANCE (45A: Traveling show with the number "Trading Taps") were gettable with adequate crosses. And speaking of gettable, the L of DOLTS (46D: Yo-yos) should have been so, but I didn't know LEVIN (53A: "This Perfect Day" novelist, 1970) and guessed nEVIN for some unknown reason. I should have run the alphabet in my head, of course, and will make it a New Year's resolution to do so more consistently when faced with such a square. Oh well. I'm not letting it dampen my spirits.
The rest of the grid was filled with enjoyable, interesting stuff. Right off the bat I said to Frannie "I don't know what the answer to 1A is, but I already know I'm giving it an A." This, if you're not familiar with this blog, was in reference to a system that our colleague Colum started of rating the first Across clue in every puzzle. A good clue in that spot can really set the tone, and today's "1A: His name was lengthened by God at age 99" (ABRAM) is just the sort of interesting factoid that can bring a smile, at least to this old trivia lover. Frannie posited "Moses," which fit, and off of which I entered "meetup" for 1D (Liaison/AFFAIR) and for 4D "Enmity" (Loathing/ANIMUS), which led to the NW being the last section I completed today, aside from the aforementioned "DOLTS/LEVIN" cross, but I still stand by my rating.
Loved the triple-nines in the NE and SW today. All six answers were good, but I especially like TROJANWAR (6A: Theme in much Greek art), FATALBERT (50A: Cartoon friend of Dumb Donald and Weird Harold) (or, "Sesame Street alter-ego who kills Ernie?"), and everybody's favorite, CASUALSEX (56A: "Benefit" of some "friends"). And speaking of that, I also very much enjoyed 37D: What "marriage is the chief cause of," per Groucho Marx (DIVORCE). Very clever guy, that Groucho. And speaking of Groucho, CIGARS (20D: Ones with big butts) had an amusing clue, too.
I won't go on and on, but there are just a couple other answers OFNOTE that I would like to highlight. I loved RHETORIC (14D: Stump speeches, often), especially as an "ending" word, as these are usually filled with Ss, Es, and Ts. And our prime-number-loving friend Huygens will certainly appreciate the inclusion of RIEMANN (7D: Mathematician with a hypothesis unproven since 1859).
A satisfying Saturday.
Favorite clue/answer - 39D: They'll stop traffic (SIRENS), but only when thought of as a tie-in with the TROJANWAR clue.
p.s. Can anyone explain CALI (44A: City famous for bad traffic) to me?
p.p.s. Nevermind, I looked it up. It's a city in Columbia. One in which, I'm assuming, the drug trade is a problem. Tough fill!