Theme: Where's my cape? - Actually, it's PACE that has been changed up and hidden in the middle of the theme entries.
20A. Madison or Jackson, e.g. : STATE CAPITAL. Wisconsin/Mississippi
32A. Workplace social event : OFFICE PARTY. 'Tis the season.
41A. Camper's gift from home : CARE PACKAGE
53A. Deviation from a normal routine, and a hint to this puzzle's circles : CHANGE OF PACE
Argyle here. We've gone from C.C. to C.W. There are circles and they help but the jumbled letters are easy to spot if you sussed the reveal.
Across:
1. Big name in designer bags : PRADA
6. Wild guess : STAB
10. "Oh, darn!" : "DRAT!"
14. Edmonton NHL player : OILER. (hockey)
15. Caen's river : ORNE. In Normandy, northwestern France.
16. World's longest river : NILE. The Orne, 110 mi; the Nile, 4,258 mi; both 4 letters.
17. Gets dirty : SOILS
18. Facts and figures : DATA
19. "My life. My card" co. : AMEX
23. Start of something? : ESS
24. Figs. : NOs. (numbers)
25. Golf lesson subject : STANCE
29. Little taste : SIP. Neat!
30. Illegal diamond pitch : SPITBALL
36. MADD concern : DUI
37. Scottish denials : NAEs
38. Many a Monopoly rd. : AVE.
39. "__ No Sunshine": Bill Withers hit : AIN'T
40. Emancipation Proclamation first name : ABE
45. Like the Titanic : ILL-FATED
47. Monk's title : FRA
48. Put up a fight : RESIST
49. Bikini part : BRA
50. Float up and down : BOB. Must Resist Mental Picture. gave in(1:29)
57. Traffic complaint : [HONK!]
60. Prejudicial view : BIAS
61. Churchgoer's donation : TITHE
62. Figure skating leap : AXEL
63. Tackling a problem : ON IT
64. Bygone anesthetic : ETHER
65. Shopping bag : TOTE
66. Cravings : YENS
67. Salon employees : DYERS
Down:
1. Wild West law group : POSSE
2. Laugh-a-minute types : RIOTS
3. Name after 39-Down : ALIAS. 39D. Police blotter letters : AKA. "Also Known As"
4. Shoulder muscle, informally : DELT. (Deltoid)
5. Pesticide poison : ARSENIC
6. Coke and Pepsi : SODAs
7. Catch : TRAP
8. Voting against : ANTI
9. Skedaddles : BEATS IT
10. "CSI" facility : DNA LAB
11. Canyon edge : RIM
12. Pub choice : ALE. and 52D. Pub choices : BEERS
13. Apt name for a Dallas cowboy? : TEX
21. Deal with it : COPE
22. Divorce proceeding rep. : ATTY. (attorney)
26. Gymnast Comaneci : NADIA
27. Stuck : CLUNG
28. A-list group : ELITE
29. Sally, to Charlie Brown : SIS. (little sister)
30. Fed the piggy bank : SAVED
31. Word in some private school names : PREP. Preparatory school for further education.
32. Broadcasting : ON AIR
33. Story with a lesson : FABLE
34. Senses : FEELS
35. Remove, as a rind : PARE
41. Payment option : CASH
42. "Way to go, kid!" : "ATTA BOY!"
43. Hardly a buzz cut : AFRO
44. Skillfully made : CRAFTED
46. Prone to flip-flopping : FICKLE. Remember the Flying Fickle Finger of Fate?
49. Triumphs over : BESTs
50. Get clean : BATHE
51. Earth pigment : OCHER
54. Four and five, but not six and seven : NINE. 9, not 13.
55. Dieter's setback : GAIN
56. "That's a shame" : PITY
57. Bowler or boater : HAT
58. Kitchen gadgets brand : OXO
59. Common URL ending : .NET
Argyle