Country music singer Ricky Van Shelton, who covers the Elvis song "Wear My Ring Around Your Neck" for the film, has a cameo as one of the Flying Elvises in the airplane as confirmed by Shelton in an interview at the time of the film's release. (He did not, however, jump from the plane).
Jack Singer's detective agency is on the same floor of the same building as that of Max Bialystock in The Producers (1967). The door to Max's office is shown in one scene in the hall; Jack is just down the hall and to the right of Max.
The trivia items below may give away important plot points.
At the poker game staged by Tommy Korman (James Caan), perhaps as an omen of bad things to come, Jack Singer (Nicolas Cage) wins with the "dead man's hand", a pair of 8's and aces, before losing 65,000 to Korman with the "unbeatable" straight flush.