Even during a two-week vacation, it was hard for me to do much in trying to give birth to a Traveller campaign, focusing on science-fictional insanity to the exclusion of work or the people I was with.
One thought is that each star-system or region within an empire might have its own special holidays. On worlds with a pronounced Japanese descent, they might have a special commemoration of Day 218 (corresponding to the date August 6th in the old-old calendar when the first atomic bomb was dropped on Hiroshima).
There is actually a Noh play, done in English, where the spirit of Oppenheimer regrets the work he did designing the atomic bomb, but is forced to revisit Hiroshima on the anniversary and be tormented by visions of the past, until a Buddhist spirit-king shows him the way to liberate his soul with a lot of Buddhist something something something. The play is re-done every year, long after people understand Aynshunt Inglish and must follow along with a translated libretto.
If Noh theater could last until the future, it would be about 4,250 years old at the time of the Traveller game. It only looks slow now because the old dialects and the old gestures laden with meaning are done and pronounced slowly and reverently with attention to detail.
The text: http://blogs.usyd.edu.au/oppenheimer-noh/