Daylight (savings time)? Saved.
Probably far from the first person to come up with the idea, but just puts calendar events (via .ics subscription/import) for reference to any Daylight Savings timezone changes.
Motivation: I work on CME related trading from Sydney. Who knows when Chicago starts to do DST? Or for that matter, how does it even line up with Sydney which also does DST?! What system settings (hopefully none!! because just describe everything with TZ!!!) need to change??
The docs/ folder hosts static generated ics files, hopefully with long enough years that it can serve us for a while. If the timezones I care about change DST rules I'll be sure to regenerate, else feel free to raise an issue. (A wise colleague raised to me to just generate 100 years and it'll be "good for life"! What a great idea.)