For my sis's hen, we all went to Westport. 19 stayed for the two nights, an extra three came up for the Saturday. There were 22 in total, ranging in age from early 30s up to 50s. We booked accommodation at the Helm down near the Harbour, there's a lovely pub underneath the apartments and so we all got together there on the Friday night, it was great, a real ice-breaker. We had two activities on the Saturday - we did a nude man art class (sis is an art graduate) and then an 80's dance class. The theme was 80's fancy dress and it was up to everyone what theme they put on it. One of the girls went as Cher, another one went as Tina Turner, another one had got a lime green jumpsuit from somewhere and backcombed the life out of her hair, I went as Krystle from Dynasty, it was mad. Went out for dinner and then to a nightclub with an 80s/90s theme. We booked the two classes through henparty.ie (they arranged the location and the activities, we just literally had to turn up) and then arranged the rest ourselves.
There are so many things you could do. I had mine a few weeks ago and we did the Victorian Escapade in Mullingar, it's a Downton Abbey themed event where you dress up as servants for the first part and as ladies of the manor for the second part. It was absolutely amazing. There's also the Causey experience nearby where you can milk a cow, go bog-jumping, bake scones, paint the bride's story on a wall.
Where are you based, what location are you thinking of? What kind of thing do you think would appeal to the bride? Wrong time of year for glamping, but you could do a tea party, make fascinators, do a treasure hunt, a spa day (a lot of hotels have spa packages). Just keep the location in mind....a lot of my friends are mammies so I didn't want a location that required hours of travelling to get there.