The bureau of labor statistics says that 0.7% of the population worked in farming/fishing/forestry in 2006. That's already a tiny pecentage, and advances in robotics are likely to drive it even lower. From the same site, construction and extraction employee 5.5%, maintenance and repair 4%, production 7% and transportation 7%. To me, that seems like a pretty exhaustive list of the basic requirements for survival: shelter, food, and even all the mass produced products we fill our homes with, and the time to distribute everything. And don't forget that our houses are bigger then ever, we eat more then ever, and we consume more products then ever. So what if we somehow shared these tasks? What would your day be like?
Monday through Friday, you'd arrive at work at 9. Until 9:03 you'd work in the garden. 9:03 - 9:30 you'd help a neighbor build his house. That done, you'd spend until 10:04 producing goods for your home: chairs, electronics, boots. 10:04 - 10:23 you'd keep the machines giving you this amazing productivity maintained and working, then you'd drive around until 10:47 dropping off the food and products you'd produced earlier. You could now wipe your brow, and call it a day. Less then two hours, and you've produced everything you need.
On the one hand, this is an over simplification: you haven't spent your 2 minutes preaching the word of God, or your 5 minutes teaching elementary school children. At the same time, a slight reduction in consumption and a slight increase in efficiency could account for all the remaining positions.
So it appears we could get by working an hour a day, or one day a week. Technology is driving these requirements down as well: how long before the 24 minutes spent driving around can be taken over by a robot? What do we do with the other 4 days of work we do? And why can so few people spend their days writing music or painting art?
We have a day's worth of really critical work each, and its falling. Its like musical chairs: everyone's trying to find their full employment, but there's just not enough. So we've got a massive legal system, and billions spent on advertising, convincing people they want more then they need. Why? What if employment was optional? Give rewards to those who do it anyways, especially those who do jobs that nobody else wants to or can. Sure, people would choose not to work who otherwise would, but couldn't we muster a couple hours a day? What would life be like then?