Captain's Log: A quick and easy way to set the stage for an episode. Mental masturbation aside, there really isn't any rhyme or reason to the decimal digits; the general rule is that 1,000 stardate units are equal to one year, the normal timespan between TV seasons. Starfleet is still using the Roman calendar at the time of ENT.
Dawson Casting: Most of the cast is semi-plausibly close to the ages of recent Starfleet Academy graduates. However, John Cho is a 37-year-old playing the 21-year-old Sulu. Karl Urban is also 37, though he's closer to his character's official age of 30. And Zoe Saldana (Uhura) is 31.
Fake American: Kiwi Karl Urban as Dr. McCoy. And pulling it off so well that he is almost indistinguishable from the Atlanta-born DeForest Kelley.
Interestingly, the most blatant example from the original series is averted. Leningrad-born but American-raised Anton Yelchin plays Chekov, originally played by American Walter Koenig with a fairly ridiculous Fake Accent. Yelchin kept the accent, purportedly as an Homage, but just because he's a Russian/English bilingual native speaker doesn't necessarily mean he can realistically speak English with a Russian accent.)
Agent Kim makes a cameo as a Starfleet instructor.
Chris Doohan, son of original Scotty actor James Doohan, plays Scotty's assistant in the Enterprise transporter room. He and his brother Montgomery had previously appeared as extras in Star Trek: The Motion Picture.
Playing Against Type: The case could be made for several members of the cast, but the biggest examples are probably Karl Urban as the cantankerous McCoy instead of a badass warrior, JohnCho as a grade-A asskicker instead of his frequent comedic fare, and Eric Bana (and not Zachary Quinto) as the Big Bad.
Promoted Fanboy: Director J.J. Abrams actually downplayed his enjoyment of modern Trek to emphasize his love of the original series. Screenwriter Roberto Orci is an admitted fanboy as well. And Simon Pegg, who holds the now-famous irony of his statement on Spaced that odd-numbered Trek films suck.
Tyler Perry, of Madea fame, was a Trek fan, they got him a guest appearance as the Dean of Starfleet Academy. Randy Pausch, who listed being captain of the Enterprise as one of his dreams in "The Last Lecture" appears as a bridge member of the Kelvin. He walks past the captain's chair, says, "Captain, we have visual", and is not seen again.
Most cast members agree that Karl Urban is the biggest Trek geek in the cast.
Real-Life Relative/Casting Gag: Spock mentions that Vulcan and Romulans share common ancestry. One of the Romulans shown when Kirk and Spock beam into the Narada is actually Zachary Quinto's brother Joe.