Spacewar on a DEC PDP-1 at the Johns Hopkins Uni summer fair in 1970. They had 2 seats and would let a player keep their seat until they lost. I nailed down one of the chairs for almost an hour.
Then there was Star Trek on my computer club's Apple II. After that I did the whole Origin trajectory: Wing Commander, Privateer, and MOO, and the Lucas Arts X-Wing, TIE Fighter, and XVT. Even dabbled a bit in EVE. I guess I've played some space games!! When I learned to code, in college, I ported Peter Langston's EMPIRE to a Gould SEL running UTS-32 and spent a lot of time playing that, and rogue, and later hack. [Edit: I also coded on MUDs in the 80s; if you ever used UberMUD or UnterMUD or any of the MUD engines with a disk-based persistent store, that was my code]
My best/worst gaming "derp" moment was in one of the Wing Commander games, when you are supposed to drop the Temblor Bomb on Kilrah, I fought for hours to get through the Kilrathi navy and slew many many of them for what seemed like hours. I complained to a friend about how awful that mission was and he said "that'll teach you to read the mission briefing" -- apparently there was a stealth device you were supposed to engage and the mission was a milk run, my hours-long battle with the entire Kilrathi fleet was a completely stupid waste of time.