Some of you might get a bang out of this one. A couple of guys have set up a site that allows you to send a time-stamped email.
As they put it: "FutureMe.org is based on the principle that memories are less accurate than emails. we strive for accuracy."
Of course, you can configure your own email programme to send post-dated email (I sometimes send myself "reminders" of meetings or suchlike -- sad, I know).
But the fun thing about the FutureMe site is that many users choose to make their emails public, so you get to read what other people have sent to their future selves. Here's my favourite:
If you haven't gotten laid since the time I wrote this, what the hell have you been doing wrong?!
(written Wed Sep 3, 2003, to be delivered Sat Sep 4, 2004)