Two things:
So it seems like you can either have the calendar always pop up, or only during morning and/or evening (or of course never) as shown in
@Bokonon's post. Well, I guess I can live with that, but it would be nice if it had a bit more intelligence and popped up a likely destination if and only if there is a calendar entry with an address that it detected which is upcoming. If there are no events (with addresses) coming up, then don't pop up the calendar. I mean I guess it's nice for people to see what their agenda is when they boot up the car, but I'm guessing that most people that care have already checked their daily agenda long before they reach the car.
Second: if your calendar has teleconferences in it, it does show that and it looks like it has an easy way to press a button to dial in to it. That's pretty nice.
But again, to reiterate: don't bother popping up a calendar if there is nothing upcoming that I can't take an action on (either an address of a teleconference #).