SIGHT-SINGING ANSWER: Theme from “Close Encounters of the Third Kind” by John Williams.

Across 
1- Pass out METE
5- Bright lizard AGAMA
10- Poems of praise ODES
14- Opera highlight ARIA
15- Catering hall? MANOR
16- Glow AURA
17- Early Tonight Show host PARR
18- Nimble AGILE
19- Jazzwoman Valaida SNOW
20- Fret STEW
21- Munchausen moon-dwellers SELENITES
23- Connections INS
25- Jazz pianist Mosca SAL
26- Politician at the end of his term OUTGOING
31- Downhill racers SLEDS
35- Lawyer’s org. ABA
36- Hair problem SNARL
38- Stony gray SLATY
40- Frat party costume TOGA
42- Hellenic GREEK
44- Kind of modern jazz FREE
45- _____ Ste. Marie SAULT
47- Nairobi’s nation KENYA
49- Court call LET
50- Eastern despots TSARS
52- One of the 12 tribes of Israel NAPHTALI
54- ___ Darya (Asian river) AMU
56- Is afflicted with HAS
57- Spanish farmer CAMPESINO
62- Pre-owned USED
66- Switch suffix EROO
67- Monday in Madrid LUNES
68- Irk a cowhand RILE
69- Delighted a jitterbug SENT
70- Foot bones TARSI
71- Actress and columnist Chase ILKA
72- Affectedly dainty TWEE
73- Opens a letter SLITS
74- Timetable, for short SKED

Down 
1- Garmin download MAPS
2- Quod ___ demonstrandum ERAT
3- Road gripper TIRE
4- Nocturnal insect EARWIG
5- Piling up AMASSING
6- Old name for pot GAGE
7- Indigo ANIL
8- Embedded spies MOLES
9- Rock venues ARENAS
10- Drying oven OAST
11- 1984 Sci-fi flick DUNE
12- Lusty god EROS
13- Sometime musical instrument SAW
22- Ailments ILLS
24- Rejections NOS
26- Grain felt by the spry? OATS
27- Submarine UBOAT
28- Spanish river TAGUS
29- British stool pigeon NARK
30- Politician Mark GREEN
32- Jazz guitarist Mark ELF
33- “Our Gang” girl DARLA
34- Heavy metal STEEL
37- Miss Horne LENA
39- Himalayan snowman YETI
41- According to ALA
43- Curvature of the spine KYPHOSIS
46- Drum device TRAP
48- Eureka! AHA
51- Separates metal from ore SMELTS
53- Aggravation TSURIS
55- Classification of suspects USUAL
57- Ship’s company CREW
58- Primo AONE
59- Small particle MOTE
60- Cross inscription INRI
61- What folding drums do NEST
63- Corn tassel SILK
64- Sommer of film ELKE
65- Grateful folk? DEAD
66- Part of i.e. EST