spatiotemporal calendars

i want a calendar that is built - from the ground up - realizing that people traverse both space and time. in other words, i want certain reminders to occur when i arrive at a particular space-time, not just time. a calendar that operated only in the spatial domain, and not the temporal domain, might have send me a reminder when i arrive next in nyc, or on campus. i often have to remember, for instance, to go to the office upon reaching campus, but i am stuck making a reminder in time, and hoping that i am around at the time the reminder goes off, and not busy. i may want spatiotemporal reminders as well, ie, remind me to call my friend when i get back to nyc and it is september. alternately, when i'm on campus, i'd like to know about seminars that i attend (but i don't care about them when i'm out of town). i believe this would be a very useful function for many people. given the iPhone knows where i am all the time, and what time it is, it seems like a perfect app. i can imagine creating a calendar for various locations in my google account, ie, home, office, new york, europe, etc. then, in each calendar, i can create appointments at specific times, or at arrival times, or arrival times between certain dates/times. appointments could potentially span several calendars (ie, when i'm in baltimore or new york, do something). somebody who makes iphone apps: please make this for the world. thank you.