Google alerted me that I should leave for Santa Barbara "now".
Which was really, really weird for me, since I was already halfway there (from Phoenix).
Apparently, it had read through my emails, seen a receipt for sigur ros tickets from ticketmaster, figured out where I was, and already calculated how long it would take me to get there.
That is insanely awesome.
If you had an event in a calendar which had something in the "Location"-field it took the location you should be at from there.
Still it is a "whoa" moment. :)
If you do get to the restaurant around the corner and stop then it should realise that it may need to remind you.
Anyway, I've signed up for it today. I like the idea in principle, and I understand how hard it is to get this right. I assume it will get better over time as they tweak it, so it's worth giving them a fair crack of the whip.
I was robbing a bank and Google alerted me that I should leave "now".
Which was really weird for me, since I had a lot of gold to transport.
Apparently, it read through my emails, seen a glitch from other galaxy, figured out portal has opened, and already calculated how long it would take for the aliens to invade the earth.