Four across and two down. I like having several theme answers, and especially when they appear in both directions, as they do in this puzzle.
The theme is revealed at 38A: It can precede the starts of 16-, 26-, 43- and 58-Across and 10- and 33-Down (bar). The theme answers are:
16A: #1 hit (chart topper)
26A: Some 1960s-'70s attire (bell bottoms)
43A: Watch (keep an eye on)
58A: However (nonetheless)
10D: Playground game (hopscotch)
33D: Manhattan Project and Operation Overlord (code names)
Having good theme answers is one thing, but the words made with the addition of bar are all good ones. That's something else. Bar chart, barbell, barkeep, bar none, barhop, and bar code. All good. Tough to pick a favorite, but I'll have to go with bar none.
Some lively fill as well. To tie in with bellbottoms, we have 27D: '60s guru Timothy (Leary). He coined the well-known phrase, "Turn On, Tune In, and Drop Out." If you don't know much about him, you can read more here. He led a most interesting life, and his ashes are somewhere in outer space.
47A: Spa treatment (mud bath). I've had several spa treatments and have to say that the mud bath was the best--bar none! After being painted head to toe with fragrant, mineral-rich mud, I was wrapped up like a burrito. I didn't make any sounds that resembled Brr (28D: Shiverer's sound), because I was under heat lamps for 20 minutes. Note to self...do that again soon.
64A: Deletes, with "out" (Xes) got the better of me in an earlier puzzle. Today I was ready for it.
30D: Strip under the mattress (slat) seemed like a rather racy clue for such a benign answer. I'll leave the rest of that to your imagination.
Several entertainment answers that were easy enough. 19A: Country's McEntire (Reba), 40A: Alan of "Betsy's Wedding" (Alda), 46A: Carter of "Gimme a Break!" (Nell), 63A: Prince's "Raspberry __" (Beret), and 41D: NBC hit starting in '75 (SNL). I wasn't sure about one of them but was able to get it from the crosses.
Sussed out the only sports clue. 44D: Mourning of the N.B.A. (Alonzo). My first guess had an S in place of the Z, so I ended up with soars for 62A: Skyrockets, rather than the correct answer, zooms.
Other sassy words were 1D: Stretchy synthetic (Lycra), 59D: "La-la" preceder (ooh), 2D: Sounded content (aahed), 31A: Potpourri holder (sachet), 52A: Madrid museum (Prado), and 39A: Muslim pilgrim's goal (Mecca).
There's one I absolutely don't get, but I know I've got the right letters in place. If no one comments about it here, I'm sure someone will somewhere.
I hope you enjoyed the long weekend. Ours was peaceful and quiet...a nice change.