I'm a bit of a schedule junkie (I carry around a Palm Treo and I also have two notebook agendas and a wall calendar - they all serve different purposes, okay??), so I discovered something of an e-Holy Grail of scheduling: Google Calendars. Does anyone else have a Google Calendar? You put in your schedule (it can also sync with a bunch of different computer scheduling software, so I sync it with my Palm), and you can see your friends' schedules superimposed on your schedule, so you can see when you're both available. You can also automatically invite your friends to stuff and they can RSVP right in the system. You can set how private you want your calendar to be. So like, my boyfriend and my very good friends can see everything in my calendar, but everyone else just sees "Busy" for all my appointments.
Since it's Google, I'm willing to bet that it can juggle time zone differences.
So if you want to be a crazy scheduling junkie like me, we can all get Google Calendars and fill in the important stuff (like going to Singapore or visiting family), superimpose everyone's calendars at once, and see which pockets of time are agreeable to everyone!
And that system can be used over and over again. Plus it's a neat thing to have for yourself.
Anyway, that's my far-out idea. I realize it's kind of a lot to implement. But I couldn't help myself - I love Google Calendars!