July 08, 2015
As a tennis player, I often need to know when sunset will be (since the outdoor courts where I play don't have lights). Conveniently, Siri can tell me the time of sunrise and sunset. You cannot only find the time for today but also for any day of the next week. (Note, however, that Siri won't give you information for dates in the past.)
June 29, 2015
If you need to call someone, but it's not convenient to place the call right now, you can use the Reminders app to help you remember to make the call later. If you use Siri to create the call reminder, you'll be able to call the person directly from the reminder notification.