Theme: PUT YOUR FOOT DOWN
4. Sunday dinner side dish : ROASTED POTATOES
6. Driving : AT THE WHEEL
6. Driving : AT THE WHEEL
10. Summer Olympics event since 1996 : BEACH VOLLEYBALL
31. Gravy thickener : CORNSTARCH
61. Body part whose parts are aptly found at the bottom of this puzzle's four longest answers : FOOT
Melissa here. Not only are the theme answers all down, but also all except one are positioned at the very bottom of the grid. Nice.
Across:
1. Drone sound : WHIR. Not BUZZ.
5. Spicy dip : SALSA
10. French flag couleur : BLEU
1. Drone sound : WHIR. Not BUZZ.
5. Spicy dip : SALSA
10. French flag couleur : BLEU
14. Parade celebrity : HERO
15. Cotton swabs : Q-TIPS. Appropriately, right next to ...
16. Pair on a Disneyland hat : EARS
17. Verdi highlight : ARIA
18. It's prohibited on many highways : U-TURN
19. Vast landmass : ASIA
20. Musical Christmas staple : MESSIAH. Handel.
22. Culinary student's assent : YES CHEF
24. Native American symbol : TOTEM
26. Bit of cheer? : RAH
27. 22% of the U.S. Senate : WOMEN. Appropriately right next to ...
30. WWII female : WAC. Women's Army Corps was the women's branch of the United States Army.
32. Program breaks : TV ADS
36. Enthusiastic : AVID
37. "Good Lord!" : OH GOD. That's what he said.
39. Miscellany : OLIO
40. [Uh-oh!] : GULP
41. Big name in threshers : DEERE
42. In __ of: replacing : LIEU
43. City ENE of Reno : ELKO. Perped.
44. One of pop music's Papas : DENNY. Dennis Doherty was a founding member of the 1960s musical group The Mamas & the Papas.
46. Takes a load off : RESTS
48. Mil. officers : LTS. Lieutenants.
49. High-IQ group : MENSA
50. Perilous hisser : ASP
52. In check : AT BAY
54. Succeeding like nobody's business : ON A TEAR. Wictionary definition: Engaged in a continuous, fast-paced procession of actions or events, especially with favorable results.
58. Like most kosher frankfurters : ALL BEEF
62. Water sport : POLO
63. Only inanimate zodiac sign : LIBRA
65. Iams alternative : ALPO
66. "Quite so" : TRUE
67. Historical period : EPOCH
68. Slimming procedure, briefly : LIPO
69. Shopping club : SAMS
70. Swearing-in rituals : OATHS
71. For fear that : LEST
Down:
1. "Careless Whisper" pop group : WHAM
2. "__ comes trouble!" : HERE
3. Eye part : IRIS
5. Weightlifting maneuver : SQUAT
7. "Elementary" co-star Lucy : LIU
8. Nimble : SPRY
9. Ed with seven Emmys : ASNER. The first actor to win an Emmy award in both comedy and drama genres for the same role (for the character Lou Grant in both The Mary Tyler Moore show and Lou Grant). List of awards and nominations received by Ed Asner.
11. Word with back or whip : LASH
12. Historic canal : ERIE
13. "Aim High ... Fly-Fight-Win" military org. : USAF
21. Non-neutral atom : ION
23. Took a load off : SAT
25. Purplish hue : MAGENTA
27. Ante, e.g. : WAGER. Ohhh ... I was thinking the prefix.
28. Small egg : OVULE
29. Takes full advantage of : MILK. EXPLOIT didn't fit.
33. From far away (perhaps very far) : ALIEN
34. See 51-Down : DIETS
and 51. With 34-Down, really retro eating programs : PALEO
35. "The March King" : SOUSA. John Philip Sousa composed 136 marches, including Semper Fidelis (1888
37. Unexpected : ODD
38. Susan of "L.A. Law" : DEY
47. Ottawa-to-NYC dir. : SSE
49. Prefix with ware : MAL
53. Vague discomfort, with "the" : BLAHS
54. Makes a choice : OPTS
55. Romance writer Roberts : NORA
56. Grad : ALUM
57. Longtime "Live!" host : RIPA
59. Author Wiesel : ELIE. "We must not see any person as an abstraction. Instead, we must see in every person a universe with its own secrets, with its own treasures, with its own sources of anguish, and with some measure of triumph."
60. Omar of "Shooter" : EPPS. Never heard of this USA Network series. It originated as a film in 2007, where the role of Bob Lee Swagger was played by Mark Wahlberg. That film is actually based on the book Point of Impact by Stephen Hunter, which is inspired by a real Vietnam sniper. More here.
64. Plant sci. : BOT. Short for botany.