Create your own time capsule of a memorable moment using this iPhone adaptation of the popular web-site, FutureMe.org.
Write a letter, add a photo, set a date (30 days minimum!)...
...and send it off to the future and surprise your future self!
You can also read your letters from the past, as well as the "public, but anonymous" letters recently delivered from the past to other FutureMe users.
See? Time travel actually isn't all that hard!