Theme: The unifier captures it perfectly, so let's go with it:
61. MLB rally killers, briefly, and a hint to what's in the four longest puzzle answers: DPS. In baseball, a Double Play occurs when the defenders are able to make two OUTS on one hit ball. This can occur in a variety of ways, but the most common is when a runner on first base is forced out at second, and the batter is also out at first base to complete the play.
As we shall soon see, each theme entry also contains two OUTs.
21 A. Ring result: BOUT OUTCOME. For reasons that are unlikely to appear any time soon, the square stage where a boxing match is fought is call a ring. This event is called a BOUT. One boxer usually losses while the other wins. Occasionally there is a draw. Either way, that result is the OUTCOME. What sneakily is concealed there is a pair of OUTs.
32 A. Unlicensed rainbow catcher: TROUT OUTLAW. You need a fishing license to catch fish. Otherwise you can become this fill. The clue is a clever misdirect, but the answer is contrived, and you're highly unlikely to ever encounter that phrase again.
41. Camporee, for instance: SCOUT OUTING. A camporee is a local or regional gathering of Scouting units for a period of camping and common activities. In my Boy Scout years, we always had a two week stint at camp Miakona in the summer. There were other troops there, but I don't recall a lot of common activities; so I'm not sure if that counts. Maybe we were on the OUTS with them. We did do some tent camping, though, throughout the year.
53. Tap water: SPOUT OUTPUT. This is self-explanatory, but again contrived - though accurate. That is where the water comes OUT OUT from.
Hi, Gang, JAzzBumpa here, not OUT somewhere else. Contrivances aside, I'm rather in awe of this theme, where each two word entry has OUT as the end of the first word and again as the beginning of the second. And with the playoffs beginning and the end of the season drawing near, a baseball-related theme is welcome. Watch for many DPs in these games. And let's see what's ahead in this puzzle.
Across:
1. Composer Bartok: BELA. [1881-1945]. One of the most prominent 20th century composers.5. Word with ship or school: YARD. One for work and the other for play.
9. Restoration locations: SPAS. Relax and be pampered.
13. Beasts that work in pairs: OXEN. Yoked bovines.
14. Largely phased-out ersatz fat brand: OLEAN. The brand name for olestra, an indigestible artificial complex fat. It was phased out due to unpleasant digestive issues - unpleasant unexpected side effects. Also the name of a city in New York
16. Org. for fur foes: PETA. People for the Ethical Treatment of Animals. An animal rights organization founded in Norfolk, Virginia in1980 and led by Ingrid Newkirk,
17. Envelope-directing abbr.: ATTN. To the attention of the intended recipient.
18. "Out of Africa" setting: KENYA. A democratic republic on the east coast of Africa.
20. Three at the start: TRI-. A prefix indicating three of something.
23. 1993 coming-of-age baseball film, with "The": SANDLOT. This movie is a hoot. See it if you get a chance.
More baseball
26. Really long time: EON. Of indefinite duration. Comes into English from Ancient Greek.
27. Surround sound components: SPEAKERS. Hear here.
36. Floral accessory: LEI. From the islands
37. Urges: YENS. I thought about going to Japan, but didn't have the YEN to travel.
38. Backing: PRO-. In favor of. A rare backing prefix.
39. Place for a catcher's guard: SHIN. A bit of baseball gear.
40. Portuguese king: REI.
45. Former California speedway that was the site of a 1969 rock concert: ALTAMONT. The event in December, 1969, only a few months after Woodstock, was a violent disaster, with 4 deaths, scores of injuries, and multiple car thefts.
47. Genetics lab material: RNA. RiboNucleic Acid is a polymeric molecule essential in various biological roles in coding, decoding, regulation and expression of genes.
48. Director Jean-__ Godard: LUC. [b 1930] His first film, BREATHLESS, is considered one of the best films ever made.
58. Pre-A.D.: BCE. Before the Common Era.
59. Injure: HARM. Do damage to.
60. Willow twig: OSIER. Often used in furniture and basketry.
61. Dire prophecy: DOOM. Originally, fate. Now a tragic or unhappy destiny.
62. Nobelist Pavlov: IVAN. [1848-1936] a Russian physiologist known primarily for his work in classical conditioning and dog training.
63. Evans' news partner: NOVAK. Rowland Evans Jr. [1921 – 2001] and Robert David Sanders Novak [1931 – 2009] worked together in newspapers and then television for decades.
64. __ sci: POLI. Political Science is the study of politics and power from domestic, international, and comparative perspectives. It entails understanding political ideas, ideologies, institutions, policies, processes, and behavior, as well as groups, classes, government, diplomacy, law, strategy, and war.
65. Elizabeth of "La Bamba": PENA. Elizabeth Maria Peña {1959 – 2014] was an American actress, writer and musician. She won the 1996 Independent Spirit Award for Best Supporting Female and a Bravo Award for Outstanding Actress in a Feature Film for her role in Lone Star.
66. Torso muscles, collectively: CORE.
67. Watersports gear: SKIS.
Down:
1. Lakeside rentals: BOATS. I was thinking cottages - which don't fit - but, OK
2. Additional: EXTRA. But wait -- there's more!
3. Allowed to enter: LET IN. Like guests.
4. Cleeves who wrote Shetland Island mysteries: ANN. [b 1954] She studied English at the University of Sussex but dropped out and then took up various jobs including cook at the Fair Isle bird observatory, auxiliary coastguard, probation officer, library outreach worker and child care officer before winning the Duncan Lawrie Dagger for her novel Raven Black. Some people just can't keep a job.
5. Bed-ins for Peace participant: YOKO ONO. [b 1933] She is a Japanese multimedia artist, singer, songwriter and peace activist. She was married to English singer-songwriter John Lennon of the Beatles from 1969 until his murder in 1980. With their performance Bed-Ins for Peace in Amsterdam and Montreal in 1969, Ono and Lennon used their honeymoon at the Hilton Amsterdam as a stage for public protests against the Vietnam War.
6. Native Alaskan: ALEUT. I had Inuit. But, no. These are the natives of the Aleutian Islands.
7. Monthly expense: RENT.
8. Belafonte classic: DAY-O. AKA The Banana Boat Song.
11. Minuscule amount: ATOM. Tiny particle.
12. Ump's call: SAFE. Or out. Hard to tell sometimes.
15. Queasiness: NAUSEA. Digestive issue.
21. Reputation stain: BLOT. Often the result of a scandal.
22. Winter warm spell: THAW. Winter is coming.
24. __ ex machina: DEUS. God from a Machine. A plot device whereby a seemingly unsolvable problem in a story is suddenly and abruptly resolved by an unexpected and unlikely occurrence. The term was coined from the conventions of ancient Greek theater, where actors who were playing gods were brought onto stage using a machine - either a crane from above or a trap door from below.
28. Scheme: PLOT. A plan made in secret by a group of people to do something, often illegal or harmful.
29. K-12, in brief: EL-HI. Elementary and high school
30. Bit attachment: REIN. For controlling horses.
31. Do a number, say: SING. That's one interpretation.
32. Supermodel Banks: TYRA. Tyra Lynne Banks (b.1973, also known as BanX, is an American television personality, model, businesswoman, producer, actress, and writer.
33. Line holder: REEL. Fishing gear
34. Handling the matter: ON IT. I'll let you kn ow when I'm finished.
35. Familiar with: UP ON. Or, perhaps, in on.
39. Sirius, e.g.: STAR. The brightest star in the night sky. Its name is derived from the Greek word Σείριος (Seirios, lit. 'glowing' or 'scorching'). The star is designated Alpha Canis Majoris, with a visual apparent magnitude of −1.46
41. Lewd stuff: SMUT. Clean mind, clean body -- take your pick.
42. Pupa protector: COCOON. A silky case spun by the larvae of many insects for protection in the pupal stage.
43. 2020 candidate Beto: O'ROURKE. Robert Francis "Beto" O'Rourke [b 1972] is an American politician who represented Texas's 16th congressional district in the United States House of Representatives from 2013 to 2019. O'Rourke is best known for his 2018 campaign for U.S. Senate, which he lost to Republican incumbent Ted Cruz.
44. Inch or mile: UNIT. Of measurement.
46. Wellesley graduate: ALUMNA. Female graduate.
49. Asparagus piece: SPEAR. I wanted the less dangerous STALK.
50. Fodder for a Fire, say: E-BOOK. Fire being an E-reader. Nice misdirection.
51. Food recall cause: E COLI. A bacterium that does not belong in your food.
52. Truck stop array: SEMIS. Plural of a semi-tractor-trailer truck, also known as simply a semi-trailer truck, semi-tractor truck, semi-tractor-trailer or tractor-trailer truck, is the combination of a tractor unit and one semi-trailer or more to carry freight. A semi-trailer attaches to the tractor with a type of hitch called a fifth-wheel.
53. Send using 52-Down: SHIP. Transport an item from one location to another.
54. Finish, as a road: PAVE. Complete the construction of a roadway, generally with concrete or asphalt.
55. Algerian seaport: ORAN. A major coastal city located in the north-west of Algeria. It is considered the second most important city of Algeria after the capital Algiers, due to its population, commercial, industrial, and cultural importance.
56. Colorado-based sports org.: USOC. The United States Olympic & Paralympic Committee is the National Olympic Committee and the National Paralympic Committee for the United States. It was founded in 1895 as the United States Olympic Committee.
57. Digital recorder: TIVO. Made by a corporation of the same name.