After a nice long day of skiing, eating and relaxing in the Sun Valley resort area of Shiga Kogen, we drove up to the Japanese Snow Monkey onsen park to, well, see the monkeys!
They have a live webcam (from 0800 to 1600 local time daily) set up here: http://www.jigokudani-yaenkoen.co.jp/livecam/monkey/index.htm

Enjoy!