What are the best and most unique souvenirs/gifts from the United States?

In July I will be taking a trip to Brazil for the WYD. While there, I will be staying with one (maybe two) families. And as a thank you for letting me (and my group) stay in their homes, I would like to 'bring a gift from the US for them. It can't be anything too specific like shirts or toys for little kids as we don't know the specifics of the family. (Though in retrospect, there will be children, we just won't know how many). Anyways, I need ideas of what would be a nice inexpensive gift to show my thanks and appreciation that the whole family would use/ like.