When I was a younger there was a phone number you could call where a recording would tell you the current time and temperature. I never really thought too much about that. It was obviously an early computer generated voice filling in the time and temperature.
Now, there’s a website for the upcoming Matrix movie that incorporates your local time the right way.
Thanks to a post on Reddit, you can see how it was done. There are 1,440 copies of each trailer, one for each minute of the day. A bit of clever code picks the correct video to play based on the local time in your browser.
Not rocket science, but it did get people talking.