"Ofuro" is a bath tub where the Japanese traditionally bathe themselves. The tub is filled with hot water and when one member of the family has finished, the next one comes along and uses the same water. When all members have finished for the day, a cover is put over the tub to keep the water for the next day.
You can just about make out a metal circle thingy in the tub - that heats up the water again on the next day. We only use our tub water once though.
Japanese folks also traditionally get in the tub together with family members too - something you may have been wondering about when watching anime, j drama or commercials.
Many washing machines (like ours) comes with a device (looks like a hose with a knob on the end) that sucks up water from the tub, filters it and reuses the water to wash clothes - most ecological.
More about Ofuro at http://en.wikipedia.org/wiki/Ofuro