Sometimes I think our family is a bit strange. I grew up in a house where my mom always said, "If you're here, you're family." So any of my brother's friends who happened to be visiting would be fed (whether they were hungry or not). Also, when I was grown I'd never know who I was likely to find in my parents' house. My mom worked at various places like Goodwill and the Salvation Army and a few restaurants. She was always bringing strangers home and making them feel like part of our family.
My mom says that when she was a girl growing up in Philadelphia, if a neighbor happened to be walking past their house during dinner time her mom would pull them in off the street and feed them. I like to think that this is a sort of "family tradition". We've sort of adopted Shannon and her siblings into our family. We include them in everything from Thanksgiving to playing tennis to making meals together. Shannon stays the night at our house on a weekly basis, usually to go to church with us in the morning.
We also include any strangers or neighbors who happen to be in our vicinity when we are doing something as a family. At Halloween last year we invited all the neighborhood kids to our house for pizza and a movie. We included a little boy named Leo and his dad in our tennis practice the other day. And tonight when some teens on bikes stopped to watch us lighting fireworks, we had them helping and sharing in the fun within minutes. It just seems natural. Then again, maybe it's genetic.