I was a super nerd when I started to play Oblivion and noticed that some times during certain months that the shops would open later then normal ...
Hm, I've noticed, from time to time, when arriving at a city after normal business hours, that some joints are still open. I figured this was a glitch, though, since others were closed. Obviously, places like the Drunken Huntsman in Whiterun are an exception. Sometimes businesses close after 7pm! I came to Skyrim from WoW, which was incredibly rich on holidays, often lasting weeks. I have to admit, in addition to fishing, it's something I miss. Just the variety and the seasonal quests, too.