In the scene where Kirk is taking the Kobayashi Maru test, he is eating an apple, which is also what he is eating while recounting his tale of taking the Kobayashi Maru test in Star Trek II: The Wrath of Khan (1982). (According to director J.J. Abrams in the Blu-ray audio commentary, this was not intended to be a reference to The Wrath of Khan. At one point, he was simply told that lead actors seem cocky eating apples.)
The Korean-American actor John Cho was initially uncertain about being cast as the Japanese-American officer Hikaru Sulu, but George Takei, who played Sulu on Star Trek (1966), encouraged him to take the role, as Sulu is a character who represents all of Asia.
Simon Pegg did not audition for the role - he simply received an email from J.J. Abrams asking if he would like to play Scotty. Pegg said he would have done this for free, or even paid Abrams to be in this film, if he had not been offered a role.
Wil Wheaton, who played Wesley Crusher in Star Trek: The Next Generation (1987) and Star Trek: Nemesis (2002), recorded (digitally altered) dialogue for many of the Romulans on Nero's ship.
When Chekov manages to transport Sulu and Kirk aboard from a fall, he shouts "Yo-moyo!" This is a Russian exclamation of surprise and excitement, roughly corresponding to English "Oh man!"
Leonard Nimoy: [identity] When Spock Prime meets James T. Kirk in the cave on Delta Vega, he introduces himself by saying "I am Spock". "I Am Spock" was the title of his second autobiography, his first autobiography being "I Am Not Spock".
Randy Pausch: A Star Trek-loving Carnegie-Mellon Computer Science professor, who gained widespread fame as the author of a "Last Lecture", in which he discussed living the life of his dreams in the face of terminal pancreatic cancer, appears as the Kelvin officer in the beginning. Pausch wrote in his blog about the experience, "I got a custom-made Star Trek uniform, and my own station on the bridge, where I had lots of buttons and controls. I even got a LINE!!!!" ("Captain, we have visual.") Pausch died on July 25, 2008. His paycheck of $217.06, from working on the film, was donated to charity.
Joe Quinto: Zachary Quinto's brother, who is credited as a stuntman, is visible as a Romulan during a late scene on the Romulan ship. The people who recorded the Blu-ray audio commentary, including J.J. Abrams, remark at how much Joe looks like Zachary in the scene.
Christopher Doohan: The son of the late James Doohan (Scotty from Star Trek (1966)), appears as the current Scotty's (Simon Pegg) assistant.
Victor Garber: There is a deleted scene of Nero, imprisoned in the prison colony on Rura Penthe, being interrogated by a Klingon guard wearing a metal mask. In the Blu-ray audio commentary, J.J. Abrams identified the Klingon interrogator as being Garber from Abrams' series Alias (2001).
J.J. Abrams: [Kelvin] The U.S.S. Kelvin, on which Kirk's father serves, is named after Abrams' grandfather, and her hull number of NCC-0514 is derived from the man's birthday. This is also a scientific reference to the temperature scale named after physicist and engineer Lord Kelvin. Abrams commonly uses this name in his work, such as "Kelvin Inman" from Lost (2004) and "Kelvin Gasoline" from Super 8 (2011).