Spoiler warning: Plot and/or ending details follow.
While not a major holiday, Naomi Wildman and Neelix planned an elaborate celebration aboard the USS Voyager in 2377, including cheese pierogies, rock and roll music, and a reenactment of the historic first contact by Lieutenant Commander Tuvok. The day often meant a day off from school for Federation youth. (VOY episode: "Homestead", ST website: StarTrek.com)
In 2381, Admiral Leonard James Akaar planned to have the USS Titan relaunched on First Contact Day, as part of a morale-boosting effort following the Borg Invasion earlier that year. (TNG novel: Losing the Peace)
In 2385, First Contact Day saw a devastating attack on Mars by "rogue synths," which destroyed Utopia Planitia Fleet Yards, killed over ninety-two thousand people, and left the Martian atmosphere ablaze for at least the next fourteen years. (ST episode: "Children of Mars", PIC episode: "Maps and Legends")
- VOY episode: "Homestead"
- ST episode: "Children of Mars"
- PIC episode: "Maps and Legends"
- ST website: StarTrek.com
- TOS novel: No Time Like the Past
- TNG novel: Losing the Peace
- ENT - The Romulan War novel: Beneath the Raptor's Wing