Serve together: Rake leaves, carve a few pumpkins or take some mums and place them on peoples door steps, take hot chocolate to the librarians, etc.
Carve Pumpkins
Dress up as a family with a theme for Halloween
Go to a corn maze (this is my favorite:http://www.explorationacres.com/)
Go on a scavenger hunt
Have a bonfire and make smores
Camp out in the back yard and catch lightning bugs
Go putt putting
Go to the zoo
Go through old shoes and coats that don't fit anymore and donate them along with books and toys.
Bake something together
The whole month of October keep a jar where you write something you're thankful for on a piece of paper and put it in then open it on Thanksgiving to remind eachother of blessings.
Bob for apples
Make Caramel Apples
Go to a pumpkin patch and go on a hayride
Paint Pumpkins
Go on a picnic with a thermos of warm apple cider
Play in the rain
Tailgate with your family for a football game
Go to a highschool football game with your face painted and cheer on the team
Make a scarecrow together
Have a night where you don't use electricity and you use candles for lights and you sleep in the living room together while playing a game. (have a fire place? Roast marshmallows inside!)
Read fall books together (here are some ideas: http://www.sidetrackedsarah.com/2012/10/fall-reading-list-kids/)
Paint pictures outside of trees
Go to a farmers market
Visit a farm
Jump in a big pile of leaves
Visit a local festival
Buy disposable cameras and have everyone take a roll of photos, have them developed and give awards for best, funny, or unique photos
Make a craft for an elderly neighbor and deliver it with warm, fresh baked bread or a pie
WHY? To create memories together and celebrate being a family together!
What other ideas do you have?