ACROSS

  1 They might change suddenly

  6 Teensy bit

  9 Lively dances

 13 Piece of ancient history

 14 12/31, e.g.

 15 Nebraska's largest city

 17 Container that affects a wine's taste

 19 Printer maker

 20 Doc often signed by reality show participants

 21 Groan-inspiring piece of wordplay

 23 Show and ___

 25 The "V" of C.V.

 26 String instrument with a bent neck

 27 Hunter in the night sky

 29 Suffix for Israel or Manhattan

 31 HBO ___

 32 Ad-lib

 37 Pieces of headwear that might protect against mind reading (but probably not)

 38 Flavorful butter replacement

 39 Dashed

 40 Manzanita ___ (apple-flavored soft drink)

 41 Pictogram that helps fill in emotional cues

 45 Numbers on right-hand pages

 47 Papal ___ (image on the Vatican flag)

 51 "Any second now!"

 52 Unofficial recording

 55 Zag's counterpart

 56 Atlanta college

 57 The Chiffons hit with the lyric "And I'm gonna make him mine"

 59 Word after "truth" or "antiaging"

 60 The Super Bowl cannot end in one

 61 Canis, for dogs

 62 "Nick at ___"

 63 Rds.

 64 Existential turmoil

DOWN

  1 "Right away!"

  2 Person with followers

  3 Compound that turns litmus blue

  4 Tip for a calligrapher?

  5 "Hit the road!"

  6 Country singer Gibbs

  7 Stave off

  8 It's full of bologna

  9 "Uptown Girl" singer Billy

 10 Urge

 11 Premium locations?

 12 Give an earful to

 16 Building add-on

 18 Cause to go "Vroom!"

 22 "You ___!" ("Absolutely!")

 24 Sudoku solver's skill

 28 Taboos

 30 Use the pink part of a pencil

 33 Worth mentioning

 34 Car accessories that help in low-visibility conditions

 35 Many a Christmas tree

 36 Agenda parts

 37 Indian method of cooking

 38 "The future is not looking good for you" sign

 39 Cozy, wrapped garments

 42 Seeping

 43 "You should come along!"

 44 Consume

 46 Walk with confidence

 48 Do great on an exam

 49 Some pink wines

 50 College-level HS classes

 53 ___ disease (tick-borne illness)

 54 Hindu discipline with poses

 58 Marshy area