The studio behind the Middle-earth MMO teased players with the foreknowledge that there would be a special and secret event on March 21st. In quick order, the community rooted it out and discovered that it was a quest that led to the acquisition of a new type of armored goat mount. Cue lots of collaboration between players and servers to solve the puzzle.
The particular quest is called The Secret Stone and requires players to have completed the introduction to Northern Mirkwood. To complete the quest, riddles and codes will need to be solved, but the community has already done the heavy lifting on that if you want the answers.