It’s difficult to pin down an exact "when," although the tradition had petered out by the late 1980s, as best we can reckon. Louis Prima falls into a different category from the other musicians you mentioned, but we’ll get to that in a minute. Rat Packer Jerry Vale says he would "get done with work some nights at five or six a.m. and go right to the golf course. I would play golf and come back and lay by the pool, go to the steam room and get a steam and rub, lie down and take a nap there."
Today, a typical* headline act plays once, usually about 7:30 p.m., and has everybody in the audience back on the casino floor 90 minutes later (more adult productions, like Absinthe, and topless revues, tend to feature one or more later performances). In the Fifties, Sixties, and Seventies, headliners were expected to work hard for the money. When Frank Sinatra worked the Desert Inn in 1952 (sharing the bill with comedian Paul Gilbert), he played 8:30 p.m., 11:30 p.m., and 2 a.m. shows. That was relaxed a bit for his 1954 Sands gig, when his second and last show, as part of the Ziegfield Follies, was at 11:15 a.m. However, during a 1961 stand at the Sands, Ole Blue Eyes was still playing the midnight slot and wrapping at 1:30 a.m., raring to take his private plane on a flight to Palm Springs.
Not even Elvis Presley was spared the midnight grind. His early years at the International found him playing 8 p.m. and 12 a.m. time slots and, on at least one occasion, he was pressed into service for a 3 a.m. show. By the end of his run, in 1976, The King was just playing once a night, at 10 p.m. (Patsy Cline fared far worse in her sole Vegas engagement, in December 1962, when she was relegated strictly to the midnight slot at Del Webb’s The Mint.)
Even after Sinatra’s rift with the Sands, Sammy Davis Jr. – love beads and Nehru jacket in place -- was still playing there, "Doing His Own Thing" twice nightly, including a midnight show. When Don Rickles first played the Strip, he was on a three-shows-a-night contract, beginning at 2 a.m. That was later ‘eased’ to a Sahara regimen of 12:15, 2:30 a.m. and – believe it or not – 4:30 a.m. shows. Neither Rickles’ career nor his trademark razor wit was dulled by the graveyard-shift hours. "I always figured it was going to be murder, but actually [the audiences] were good," Rickles told Las Vegas Review-Journal reporter Mike Weatherford.
If Rickles was one of the hardest-working men in show business, Buddy Hackett was also no slouch. During one stretch, when he was filming The Love Bug, Hackett would fly nightly from Los Angeles to fulfill his 2:30 a.m. show duties at the Sahara. Then there was the cult phenomenon that was Red Foxx’s 2:30 a.m. show at the Silverbird, where he let his "Triple XXX Rated" humor fly, a throwback to the days when his comedy albums were so racy that they were gray-market cult items.
As the sun rose, the post-midnight denizens of Strip showrooms headed home for some hard-earned sleep. But for others, the work didn’t end at sunup. Stardust bandleader Juan Garcia Esquivel and his combo would play through the night. Their last set was so late that it was followed by a 7 a.m. rehearsal, as Esquivel felt the show had to be frequently revised and kept contemporary.
The true creatures of the night were the lounge acts, like the aforementioned Esquivel. Contemporary reports of the Mary Kaye Trio describe the Hawaiian vocal group provoking vociferous, foot-stamping ovations … at 4:30 in the morning. But the king and queen of the late shift were Louis Prima and Keely Smith (who even parlayed their fame into a one-shot movie deal). Prima’s first Vegas contract, at the Sahara, called for him to play three 45-minute sets as part of a grueling, 14-hour lounge-act showcase that ended at 6 a.m.
The lounge format is something that’s largely vanished from contemporary Vegas. Two or three acts would perform in rotation, for hours on end, as gamblers either took a spell from the tables or parked their wives in the lounge. There was a bar, sometimes a buffet and – if you were lucky – a small stage. Freewheeling improvisatory acts fared best, and Smith and Prima’s routines marked them as the best of the lot. Like Rickles, they were able to use their fame to secure an easier work schedule at the Desert Inn: an 8:15 dinner show and an 11:45 p.m. stemwinder. (For a tactile description of the lounge demimonde, Weatherford’s Cult Vegas is a must-read.)
The tradition of the midnight show seems to have petered out around 1990, ushered out by – of all unlikely people – primal-scream comedian Sam Kinison, after some ill-fated New Year’s shows.
So what marked the demise of the midnight show? Part of it was the greater negotiating power of a new generation of headliners. (Who’s going to tell Celine Dion that she has to play a midnight shift?) Some of it was the collective decision of casino owners to turn the lounge – like everything else – into a profit center. No longer could you take a break from the slots, catch a bit of Cook E. Jarr’s 3:30 a.m. set, grab a quick bite in the coffee shop, and head back out for more play. No, now the lounge show (like Matt Goss’ Cleopatra’s Barge act at Caesars Palace) is often a rigorously scheduled, ticketed event.
As for the post-midnight hours, they have become the province of the nightclubs and after-hours clubs, where the young and beautiful party until dawn, then migrate to another club and party some more, before readying themselves for the "daylife" party scene poolside. The days of being serenaded by a top-rank musician in the wee, small hours of the morning have gone the way of those old casinos -- the Sands, Sahara, Dunes, Desert Inn, etc. -- where the midnight show and the lounge act reigned supreme.
