Lieutenant Saavik looks rather un-Kristen Alley like in The Search for Spock, doesn't she? It's not because of the Genesis effect, but a cinematic law we've dubbed the transuniversal monetary morphologic effect—a sci-fi sounding way to say it's all about the Benjamins. Alley's contract for The Wrath of Khan didn't include options for sequels, and her agent demanded way too much for her return. Rather than pay up, Paramount replaced her with Robin Curtis. (Source)

True Fact: Leonard Nimoy invented the famous Vulcan hand salute. He devised the salute for the Original Series episode "Amok Time" when he felt the character needed a special way to greet his Vulcan matriarch, T'Pau. He based the gesture on one used by the kohanim (read: Jewish priests) when they perform a certain blessing over the congregation. The congregation is supposed to turn its back on the priests when the blessing is performed. As a child, Nimoy curiosity got the better of him and he couldn't resist a peek. (Source)

The USS Grissom is named after real life astronaut Lieutenant Colonel Virgil Ivan "Gus" Grissom. He was with the U.S. manned space program since its beginnings in 1959 and was the first man to fly in space twice. Tragically, Grissom died during a pre-launch test for Apollo 1. (Source)

You might have noticed fur balls chilling on a table in the lounge scene and thought, "Well, that's can't be sanitary." These creatures are called Tribbles, and they are a fan favorite in Star Trek lore. First seen in the Original Series episode "The Trouble with Tribbles," the tribbles are a small race of furry critters that multiply at a rate rabbits would find scandalous. They emit calming, mewing sound when petted which has a "tranquilizing effect on the Human nervous system," which could explain why they'd be at a lounge. You think they have a Tribbles and Tonic special on the menu? (Source)

The voice of the Excelsior's turbolift was provided by none other than Leonard Nimoy, meaning James Doohann was telling off his director and friend with the line, "Up your shaft." Nimoy is credited under the alias Frank Force. (Source)