We had a FHE activity day in September, and I think that it was one of the best ones we have had. 
Of course, Moms and Dads were invited, so we had a nursery for any of the nursery aged children. 
We didn't specify older siblings could come, and we would have welcomed them, but none chose to come. 
Here is what we did.

• About two weeks before the activity day we visited each family. 
  We took them an invitation and an empty box. 
  We got paper boxes from Kinko's and OfficeMax. The invitation told them the when's and where's, but it also told them that this was going to be their FHE box, so they, as a family, needed to decorate it to reflect their family.  So, we have already given them something to do for FHE before the activity day has even arrived.  They were also instructed to bring their boxes to the activity, and that we would fill them up.
• We met altogether at first. 
  Everyone sat in a circle and was introduced and showed off their primary boxes...
• We then divided into four groups and went to separate classes that rotated.
  We had one class on lessons, one on games, one on songs, and one on refreshments. 
• Our lesson class,
  We had available the FHE resource books for families who did not already have it.
  We had lots of handouts on ideas, taken from the Friend or the resource book. 
  We also gave out pizza boxes and the instructions to make a flannel board box, if they were interested. 
• Our refreshment class
  We talked about all of the fun things we can do for refreshments. 
  I had made up a little recipe book for them, and then they made a small refreshment that didn't need to be cooked. (We made hamburgers
  out of Nilla Wafers (Bun), Grasshopper Cookie (Burger), Green Coconut (lettuce), Red, White, and Yellow Frosting (ketchup, mustard, and Mayo).
• Our Chorister did the songs
  I am not sure all of what she did, but I know she not only sang religious songs from the CSMP, but also just fun silly songs.
• Game
  In the games we had tons of games being played, with lots of handouts.

In each class they received a file folder to put their handouts in, so each family left with their box and four file folders filled with ideas.

For refreshments we had made about 6 or 7 different items from the little recipe book that was handed out and did a taster's table.