Yes, there was, and indeed they did (well, they had the option to, although we can't verify how many patrons actually took advantage of this opportunity).
According to UNLV's David Schwartz, author of the definitive biography of Circus Circus creator Jay Sarno, the (short-lived) charge was $2, although a Circus Circus fan site offers a differing account, stating that the fee was 50ยข from 2 to 7 p.m. and $1 from 7 p.m. to 2 a.m. (Perhaps Sarno hoped the levy would recoup the money he was losing by not having built any hotel rooms.)
The 1968 opening was one of those occasions when almost everything that could go wrong did, starting with the failure to meet its scheduled October 1 opening date by 17 days. When the big day finally arrived, a massive rooftop release of celebratory balloons went off prematurely when a TV helicopter tore their netting loose with its prop wash (fortunately, nobody was harmed). Star attraction Gina Lollobrigida then almost canceled her big number when a tiger with whom she was supposed to share the spotlight got a little too frisky. It was a case of no tiger or no Gina: The tiger went.
With its novel carnival midway, trapeze acts, and wandering elephant (which even flew, briefly, but that's another story ...), Las Vegas' first fully themed casino was designed to be kid-friendly, for sure, but it straddled an interesting line, with juxtapositions including a bar built into a merry-go-round, plus peepshows and a "knock-the-girl-out-of-bed" game, both of which featured topless women.
However, as you and your friends recall, the ground-floor casino could be entered from the second floor by any of three ways: The sedate could descend via a staircase, friskier patrons could take the slide, and the really daring could shimmy down a fireman's pole. Schwartz believes this gimmick lasted no longer than until 1974, when Bill Bennett and William Pennington bought Circus Circus. In a year they turned the property from a money-loser to a profitable casino, and by then the admission charge, slide, and pole were all things of the past.
