For anyone going to europe for your cruise there seems to be a great sale through delta
NY to Dublin for $154 RT+tax which comes to $379(Boston $421).
Don't ask me how they can sell a flight for $154 RT to Europe!
I checked it is available on many dates, use delta and then flexible search.
2.Mouse over planning tools at top right, click book a flight
3.Put in NYC to Dublin in airport fields
4.Click the box that says flexible weekend travel and choose which month(I did november)
5.Then click find flights