Within the game there are multiple subtle things that are often unnoticed by people.
For example:
The Kraken always cries every morning at 3, 3:15, and 3:30 without fail.
The skulls whisper to you saying things which some argue "rest in peace" or "lost the keys" with other things.
The song "We shall sail together" is in 6/8 time and in the key of B flat minor.
Something really cool the devs could do is apply these more subtle and hidden forms of trivia and make a large scale ultimate riddle. For example with the Kraken's cry and the song you could have someone goto an uncharted island located in B (from the song) 3 (from the kraken's cry) which would be just north of Sailors bounty. In order to access the next portion you could have a pirate legend play the shanty "we shall sail together" at 3 am at that location to access the next portion (yes I know they can't start the shanty anywhere other than a tavern, however you don't ever have to stop playing). I know I'm missing a ton of hidden things like that but the potential is there and the payout could just be something as simple as a set of skull fort loot that can only be done once per server.
Anyone else have weird little facts similar to these that could be used to compile an ultimate riddle?