I'm coming up on my first week in S'pore, and I'm finding that a common activity is determining the time-- somewhere else.
Both Elaine's job and our link to family and friends require communication with people dispersed about the planet. Hence "today", "morning", and "10:00 PM" are times relative to where you are. Phone calls must be carefully considered making it an appropriate time for the parties on both ends of the conversation. Computation of the time in another place on the globe is not calculus, but it does require some concentration. It's easy to get it wrong.
I recognized this was going to be an issue for us prior to leaving home, so a quick project in the shop (before it was packed) was a small "time center" with several clocks that each could be set to time zones appropriate for us to track. The clocks give some visual assurance that your calculations are correct. Of course there are widgets for your computer screen, and websites to do the calculations for you, but I thought this would be more fun. I'll be happy when it arrives, some number of weeks from now. Our family is perhaps more complicated than most. (See SF Chronicle )