I'm sure there's some extremely long and unnecessarily detailed page on Wookieepedia about this that I'm not going to look for or read, but I bet someone has come up with "official" days of the week in the Star Wars galaxy.
Some books use New Hope movie, other use the Battle of Yavin (ABY and BBY for after and before) to refer to time. Days, weeks and months kinda don’t exist, but they’ll say x galactic standard days to denote day lengths for some time frames.
"What are we watching for the experiment tonight, boss?"
"Ooh, me and my apprentice have got a doozy for you... the Star Wars Holiday Christmas Special!" "NOOOOOO...!"
"Bea Arthur! Harvey Korman! Diahann Carroll! Carrie Fisher sings! Happy Life Day, fellas! (evil Sith laugh)" "...OOOOOOOOOO...!"
Crow: "Sort of makes you pine for the good ol' days of Manos: The Hands Of Fate, doesn't it?"