Hey Flash,
I was thinking of just getting the UTC Date . A Javascript Date object is really just the number of milliseconds that have passed since 1 Jan 1970. So, what you end up with is a number that progresses in a consistent and predictible manner without having to worry about incrementing it yourself. You could take that number - a big number, being the number of milliseconds since 1970 - and then do some sort of arithmetic mangling that would result in a number that would make sense for your needs.
The idea that @acuratang has isn’t far off from mine. I just ignore location and worrying about accuracy. You can do whatever mathematical manipulation you want to ensure getting a number that makes some sort of sense.
Be creative, have fun, and I hope this helps.
Yisrael