Can be anything from studying Japanese (language school visa) to "just living" (permanent resident). It's a bit difficult to get a work visa in Japan without a professional qualification, but once you get that it is easy to stay longer. I guess most of the young foreigners are studying or teaching English while working part time, while others are mostly doing real jobs.

Playing :) Seriously, playing anything from sumo to baseball. The domestic soccer setup is big, and I have friends who play soccer for clubs. They practice whether it is hot or cold, other than for that it is good.

I have been to Japan 5 times and the longest time I spent there was 2 months. It was about 5 years ago. So no, I don't live in Japan, but I am married to a Japanese woman and the possibility that we will move there is always present. I can't say exactly what I am going to do if we move I don't even know if we will live in Tokyo or in a smaller city. I don't know if I will be working for a Japanese or foreign company or do freelance. What is sure that once I move to Japan I will finally start learning the language. You can get around without being fluent in Japanese but if you want to be well integrated into company life and have Japanese friends you will need to master the language. And I am planning to do that :)