An app that allows you to have a meeting with someone anytime both of you're available for the meeting. So it's schedule-less. Example: You want to talk to Paul. Paul wants to talk to you. But not as much. Paul is ranked "a1" in your book and you are ranked "b5" in Paul's book. Paul notes that he is in a "b5 and above" time period. Maybe he just got done exercise so he is more interested in talking to anyone (you are…
http://bits.blogs.nytimes.com/2014/02/28/will-someone-please...
Imagine needing speak with your doctor. You doctor might grab a minute sometime and then call you. You, with anxiety waiting for your test results, might take that call anytime (and in fact people do). But the doctor does not want to map out a specific time to call you as he might just have a few minutes between patients. And he will dial those from a note he has. And many will not be there when he calls. (This could in fact pre queue up just as if you are the President and you tell your secretary "get so and so on the line I will be out of this meeting in 5 minutes".)
So really this solves another problem but is not necessarily a replacement for a separate general scheduling issue.
Same concept could be adapted to, say, a handyman. He might have two hours in between fixed jobs and say "what job can I pull of where the person is home and within 3 miles from where I am right now".
(Although to be clear that wasn't the original point of the idea but now I'm thinking of that twist to it.)
[1] For example a salesman calling is normally interuptive and scheduling a meeting for something that you have only trivial interest in is not going to happen. Otoh sitting waiting for a plane which is delayed opens up the potential desire to possibly take meetings and conversations over things that you don't necessarily want to schedule.