My wife uses Siri several times per day to add events to our shared family calendar.
And I have to say, even as an Android zealot: I'm jealous. It's a far superior interface for entering calendar events. She can say things like:
"Harper has ballet at 4:30 on Thursdays and a Dentist appoint on December 7th at 1pm."
or even
"There's no ballet on December 22nd or 29th"