Writer Alec Berg had a crush on actress Dylan Tays, who plays Jerry's blonde girlfriend in episode 7.19, The Calzone (1996). Over the phone, Berg convinced Tays to go to the Oscars with him. (He was writing jokes for the ceremony one year.) Unfortunately, when he went to pick her up he found out she had a boyfriend, a photographer who wasn't too thrilled to see him. Tays had neglected to tell him about that on the phone. The incident inspired a story line in the season eight finale, The Summer of George (1997).
In the last scene, Steinbrenner, voiced by Larry David, states that he "smells a pennant." Later that year, the New York Yankees indeed won the pennant, after 15 years.
Dustin Hoffman was indeed not in Star Wars: Episode IV - A New Hope (1977). There's a popular urban legend that he played an uncredited role of an Imperial Trooper during the interrogation scene between Darth Vader and Princess Leia, but this role was actually played by actor Ron Conrad, who bore a fair resemblance to Hoffman. Supposed video of Hoffman in the scene was actually a deepfake created decades later.
Jerry (Jerry Seinfeld) decides a box of Cuban cigars to be an appropriate wedding present for George, but when he was given a box of the cigars by Susan's (Heidi Swedberg) father in season 4, he disliked them so much he gave them to Kramer (Michael Richards).
The USPS Creed actually starts "Neither snow nor rain..." So rain is, in fact, second. The creed is also unofficial; the USPS website states that while they appreciate the public image the creed gives their letter carriers and that they hope to live up to it, it was never the agency's official policy.