K.H.
These are so fun! I've done this, years ago, with a small group and we did facials and each person picked a movie to watch, complete with popcorn which each person designed. My long time friend did sundae's with everyone bring their own toppings one time and pizza's with the same "topping" concept another. My DD has done massages at her cousins when the bridesmaids got together for a Girls Night IN.
Other ideas, each person could bring their favorite game you could do facials (I do those types of presentations in my business and the ladies seem to have fun), old time candies and guessings games, reliving the era or music that they grew up in as a singing marathon could be fun. Each lady could bring a dish along with the recipe for that dish, one copy for each one there and also bring their recipe books to share ideas. The ideas are endless.
It sounds like a wonderful way to bond with friends.
Blessings
K.