One feature I've pondered is some kind of location based phone thing. IE you tell it things like "I like to go down the pub with this group of people", and it'

One feature I've pondered is some kind of location based phone thing. IE you tell it things like "I like to go down the pub with this group of people", and it'll automatically suggest that as an activity to you all if you're in a suitably small area and have the time free on your calendar.