Conversation clubs

Japanese people are very interested in speaking English. It is quite the phenomenon, as it seems that a huge majority, of people in Tokyo at least, want in some way to make English a part of their lives. Some need it for work, others want it as a tool to be able to handle foreign customers, some like the prospect of traveling to foreign countries, etc. The fact is, it just seems to be the thing to do, and as such, it is a great way to get Japanese people to open up and be very friendly with you.

They won't be using you for language practice per se, but they will be thrilled at being able to employ their English skills in order to learn more about you and your country. I recommend checking out this website for events centered on conversation and language exchange. Join one while you're in Japan and make some good friends!
http://english-conversation.meetup.com/cities/jp/tokyo/