I just found this post as a draft - planned to be posted months ago - so here it is now.
It all started with Jessica, really. Jessica gave Reuben a make-your-own-pirate-hat kit for Christmas and Reuben pulled it out the other day (January!) when Jess arrived and they made it together. With the leftover bits of black cardboard the kids made many and varied moustaches.
Reuben had great fun pretending he was Captain Jack Sparrow and was very clever at catching Jack's mannerisms.