Weddingbee boards

My H2B and I are celebrating our 10th anniversary by hosting a weekend for friends and family that includes a latemorning service and a lunch at a lovely Inn where our blended families have shared many great memories.  Given our ages (45 and 55) and those of our kids, as well as our guests, we have opted for a lovely sit down meal followed by a nontraditional reception of activites such as swimming, kayaking, canoeing, hiking, sitting on the beach, volleball, etc.  All outdoor activities enjoyed by our friends and family.  At the end of the day we will have a casual meal and say our goodbyes.  Some people will stay over, others will head home.  Here's my question...what are we going to do if it rains?  We have the banquet room but I'm in desperate need of ideas for plan B (as in Bad weather).  We will have 50-75 guests.  So far I have playing Wii...everybody plays the dancing games everytime we are together, photobooth and ......?? for 4 hours.  Your ideas, please.