Theme:
17. Has a contagious smile, say: LIGHTS UP THE ROOM.
28. Parties like there's no tomorrow: RAISES THE ROOF.
47. Gets ready for action: CLEARS THE DECK.
Reveal:
63. Remodeling projects, or a tongue-in-cheek title for this puzzle: HOME IMPROVEMENT.
Across:
1. Went 60 in a 30, say: SPED.
5. Expression of anger, maybe: SLAP.
9. Deli device: SCALE.
14. __ stick: POGO.
15. Double agent: MOLE.
16. Sense of __: HUMOR.
20. Whitlock Jr. of "Cocaine Bear": ISIAH.
21. Seal Beach's location, informally: SOCAL.
22. Self-care destination: SPA.
23. Gym top: TEE.
24. Prefix with Pen: EPI.
26. Italian bubbly: ASTI.
34. Feature of some kaleidoscopes: PRISM.
35. Google Maps suggestion: ROUTE.
36. Resting on: ATOP.
39. Mary Roach book subtitled "The Curious Life of Human Cadavers": STIFF.
42. "Good going!": NICE.
43. Keep from expiring: RENEW.
45. R&B singer Braxton: TRACI.
51. Enjoy: LIKE.
52. Spanish "that": ESA.
53. __-Ida Tater Tots: ORE.
56. Get older: AGE.
59. Airport postings: TIMES.
61. Turkey neighbor: SYRIA.
66. Nepali or Laotian: ASIAN.
67. Country singer McCann: LILA.
68. Bird house: CAGE.
69. "Dunno" gesture: SHRUG.
70. Social sci. major: ECON.
71. Auth. unknown: ANON.
Down:
1. Gymnastics move: SPLIT.
2. Equanimity: POISE.
3. Like challah, compared to white bread: EGGIER.
4. Qatar's capital: DOHA.
5. Texting tech: SMS.
6. Worst: LOUSIEST.
7. Dog food brand: ALPO.
8. Willow, to the Biden family: PET CAT.
9. Bus stop fixture: SHELTER.
10. Hostile dog: CUR.
11. Famous __ cookies: AMOS.
12. Coaster feature: LOOP.
13. Bombeck who said, "If you can't make it better, you can laugh at it": ERMA.
18. Nonbinary possessive: THEIR.
19. Word with tag or mark: HASH.
25. Trident-shaped letters: PSIS.
27. Like a big dog named Tiny: IRONIC.
29. Attraction: APPEAL.
30. Singer Patti who wrote the memoir "Just Kids": SMITH.
31. Arles aye: OUI.
32. How homeopathic remedies are sold, for short: OTC.
33. Shipping charge: FEE.
36. Path of a three-pointer: ARC.
37. Contact no.: TEL.
38. Small number: ONE.
40. Climb El Capitan without ropes, say: FREE SOLO.
41. Crazes: FADS.
44. Putting pen to paper: WRITING.
46. Come to an end: CEASE.
48. Milk choice: SKIM.
49. The Pantheon, e.g.: TEMPLE.
50. Like kimchi: KOREAN.
54. Drummer Starr: RINGO.
55. Consumed: EATEN.
56. Cries of clarity: AHAS.
57. "Oh, golly": GOSH.
58. Gulf States title: EMIR.
60. Writer/illustrator Carle: ERIC.
62. Party song title spelled out with gestures: YMCA.
64. __ Claire, Wisconsin: EAU.
65. Moving vehicle: VAN.