The very first Disneyland history research I did concerned opening and closing dates for various things throughout the Park. In 1995 I came upon this Chronology of the Walt Disney Company. (Though there is now also a Chronology of Disneyland, I do not believe that existed back then.) The result was a rough Disneyland Timeline, which became much, much better as I went through The Nickel Tour and with the release of Disney A-Z. I worked on it up until around 2000. A somewhat bastardized version of it can be found here, including additions/changes not done by me.
In the course of my research for the encyclopedia, I've continued to come across mentions of Park operating hours, entertainment, promotions, and events. At first I glossed over the hours; I wanted to get to the exciting articles! But one of my goals with this project is to give due importance to the operational aspect of the Resort, and what's more fundamental to that than the operating schedule? Moreover, I became convinced in the theoretical possibility of knowing the operating hours from all 20,000+ days of its operational history. I realize, of course, that this could never be perfect. At best I would have a record of its scheduled hours--and even at that, scheduled at one point in time. Inclement weather and attendance could change the operating hours that day and would likely not be recorded in any source I'd ever see.
With that goal in mind just the same, I embarked on a week of tedious work to add all those dates to the thesaurus database. In addition to just the dates, though, I also went to the trouble of making sure they were linked to the appropriate days of the week (Timeanddate.com provided just the tools I needed to find that information). The days are additionally linked to holidays. So, if I eventually want to find out at a snap the Park hours for all Easter Sundays, I'll be able to do that. (Please, somebody give me a reason!)
Simply creating a day-by-day chronology with hours wouldn't have been enough for me to add all those dates, though. Putting in dates allowed me to associate the other terms in the thesaurus with the various days--opening dates, closing dates, debuts, air dates, etc. I made the decision to not include specific performance information in the date terms for regular performances. That is, Party Gras has a debut date of 1/11/1990 and an end date of 11/18/1990, but every day in between does not indicate that Party Gras performed. This is partly because I did not feel that level of detail was knowable... and I also didn't want to kill myself trying to find out! Very short-term promotions are linked to the specific days on which they occurred.
As you might imagine, this part of the project (recording operating hours) is still very much a work-in-progress. It's complicated by the fact that many of my sources only give the current general operating hours, without a hint of when they changed to something else. So, my current thinking is to arrange the information provided by all of these sources chronologically and figure things later.