After my ceremony and reception (we had the reception offsite) half of my guests (parents, older folks, etc.) went to the piano bar and had a ball and the other half (us and all the younger people) met up at the Manor side pool and did some lounging, night swimming and volleyball. It was nice to just hang out and chill after all the festivities.
I think it's a good idea to keep things laid back, that day will fly by like a blur and it will be the chill moments that mean the most in the end. (taking time with your family and friends for unplanned bonding.)