I submit that this is one of, if not the best Jim Halpert/Dwight Shrute pranks:
I'm with Brad Paisley in thinking this would be one sweet trick (and pretty useful too), but I'm 99.9% sure a letter from Future Meagan isn't coming any time soon.
But thanks to this sweet site, I can write to Future Meagan. You should try it too!
It's also cool to read (with caution) some of the public entries.