17. Super-fun experience : BANGUP TIME
24. Certain baby tiger : BENGAL CUB
35. Cramming three seasons into a weekend, say : BINGE WATCHING
48. Salsa percussion instrument : BONGO DRUM
57. Securing strap : BUNGEE CORD
Melissa here. Vowel progression theme, with a few unknowns (for me).
1. Curve on a slalom, e.g. : ESS
4. Frugal folks : SAVERS. Anyone remember Jeff Smith, The Frugal Gourmet? He always said that frugal did not necessarily mean "cheap," but that you use everything and are careful with your time as well as with your food products. I miss the early cooking shows without all the absurd game-show antics.
10. Sea devastated by irrigation projects : ARAL
14. "Something tells __ should've stayed in bed" : ME I
15. Brunch staple : OMELET
16. Walk worriedly : PACE
19. Tolkien beasts : ORCS
20. Concrete strengtheners : REBARS
21. German auto pioneer : DAIMLER. Unknown for me. Wikipedia.
23. Junior or senior : YEAR
26. Grandmotherly type : OLD DEAR. As a grandmother, I don't love this clue ;).
29. Sarge's superior : LOOIE. Did not know this spelling.
30. Stand behind : ENDORSE
34. Rural stopover : INN
39. A pop : PER
40. Contemptuous one : SNEERER
41. Wolf pack member : U-BOAT
44. Natural night lights : AURORAS
52. Crowe's "A Beautiful Mind" role : NASH. Based on the book by the same name. Died in 2015.
53. Remove field heat from before storage, as crops : PRECOOL. Okay.
54. Japanese faith : SHINTO
56. Like cotton candy : SPUN
59. Owned : HELD
60. Horseshoes score : LEANER
61. Short-lived obsession : FAD
62. Neighborhood : AREA
63. Make certain : ENSURE
64. Trout lure : FLY
1. Developmental stage : EMBRYO
2. Sargasso wriggler : SEA EEL
3. Nautical stage name of comedian David Adkins : SINBAD
4. Lemony cocktail : SOUR
5. Rock concert gear : AMPS
6. Zoo staffer : VET
7. Slur over : ELIDE
8. Hire a new crew for : REMAN
9. "Shrek!" author William : STEIG
10. Historic Harlem theater : APOLLO. Has anyone else rubbed the wood?
11. Treasury collectible : RARE COIN
12. Accumulating, as interest : ACCRUING
13. "__ Miz" : LES
18. Source of tomatoes for homemade sauce : GARDEN
22. Bad beginning? : MAL
24. "Iron Chef Showdown" host Alton : BROWN
25. "Big" London attraction : BEN
27. ESL part: Abbr. : ENG
28. Citrus drinks : ADES
31. "Is This Love" singer Corinne Bailey __ : RAE
32. Power source : STEAM
33. Sandy-colored : ECRU
35. 1940s jazzman : BEBOPPER. Sneaky clue.
36. Totalitarian control : IRON RULE
37. Naval pronoun : HER
38. Having a twist : IRONIC
39. Happy hour site : PUB
42. It may form the outline for a meeting's minutes : AGENDA
43. Front-of-bk. list : TOC
45. Skedaddled : RAN OFF
46. Celestial : ASTRAL
47. Substandard : SHODDY
49. Paso __: two-step dance : DOBLE.
50. City where Joan of Arc died : ROUEN
51. Arm bones : ULNAS
54. Crystal ball reader : SEER
55. Where you are, on a mall map : HERE
56. __ Na Na : SHA
58. Bearded grazer : GNU
Here is a wonderful article about the cause our dear Melissa has been working on tirelessly the past few years. Talk about personal sacrifice. She's just amazing!