Before I came to live in Japan more than two decades ago, my family used to host Japanese homestay students, and I learned a lot about the country through those experiences. We hosted quite a few over the years, high school kids from Yokohama and Nagoya, a university student from Hokkaido and so on, and had a lot of fun as well as more than our share of linguistic and cultural communication problems (which are kind of the point). There's one unfortunate reality to homestay programs in the U.S., and that is since host families receive money for putting up their Japanese guests, homestay has been turned into a for-profit activity by some, who host as many foreign guests as their houses will hold and greatly reduce the chance for useful cultural sharing to take place. If you think you'd be interested in sharing your home with homestay students from Japan, learning from them as you help them learn about your country, please look into what programs you can find on the web. Googling homestay programs in your city is a good place to start, or consider contacting a nearby university that has an ESL department to see if they're looking for homes to place new students in.
We recommend you consider a homestay student if you want to have a great experience!