This isn't a conference, but a gathering, so there aren't any organized-ahead-of-time activities, except for those that the attendees choose to organize themselves!  Last year how we worked things was that we set up a whiteboard in the main gathering area, and people would write down activities or excursions they were organizing, as well as general notes (in example: "please keep the volume down before 10:00 am" and similar).  This system seemed to work well, and while we had very few organized activities, everyone had a lovely time spending time with each other in a relaxed setting!