Ask MetaFilter member JannaK presented the community with a puzzle that had been troubling her family for nearly 20 years. Her grandmother died in 1996 from cancer and in her last days she scribbled down a seemingly non-sensical string of characters on index cards. Nobody knew what it all meant. Then the Metafilter community solved the puzzle in 14 minutes.
According to the posting, JannaK's grandmother left at least 20 of the cards behind but neither JannaK nor her cousins could solve what they assumed were codes. Her father discovered one of the cards lying around recently, and so JannaK put it to the community. Holy moly, wouldn't you know it? The code turned out to be last prayers of a dying woman. Each letter stood for the first letter of the word in a prayer or message to God.
The back of the card was the easiest to decypher, revealing the pattern.
Our Father who art in Heaven, hallowed be thy name... etc etc etc
Having recognized the pattern and the prayer-like sentiment, community members started piecing together the front side of the card bit by bit. It all appears to be a series of thank yous and requests to god; things like "Please see that we are all happy and safe in our lives and work" and "thank you Almighty God for listening to my prayers and answering them." You've really got to read the whole thread to watch the meanings—er, possible meanings—of the code on the card unfurl.
While the analysis of the code on the back of the index card seems almost certainly correct, we'll never know for sure whether all of the guesses for the front are right. But what a touching story. And, holy crap, the internet is capable of some glorious things.