Head out to the shores of the Brandywine near the Brandywine Bridge on the Bree-land side to find some quests pertaining to this event! It is active now!
There are also additional goodies in the LOTRO Store celebrating being a pirate such as eye patches and pirate hats. All the fashion rage for the middle-earth pirate.
I do suggest you run through the events before rushing out to buy these items as most (possibly all) can be obtained by the event quartermaster.
This event is not on the community calendar but this even typically runs from September 17th through 21st. Do not delay though in case it shuts down earlier!