1
By "easiest", I mean in terms of time and attention. The idea is to have lots of time to work on projects that you enjoy. That time has to be good "maker time", not time when you're mentally exhausted from working at a job that consumes you. Think Einstein working at the patent office.
By "make a living", I mean enough money to pay the rent on a modest apartment, eat cheap food, and occasionally buy nice toys. US$24,000/year is probably the minimum.
Inheritance, sugar daddy, and living off your parents are amusing cheap-shot answers, but that's not what I'm asking about. I'm thinking that since technology has made us all so productive, it ought to be possible to work very few hours to make a passable living, and thus enjoy much more leisure time. Most people don't do that, though. People in the U.S. seem to be working harder than ever, but not getting much enjoyable leisure time. What might we find if we looked seriously at how to earn a living in a way that leaves the most time available for person projects that probably don't make money? Such projects could be anything from taking care of your kids to painting pictures to proving theorems.
Example: An entrepreneur friend of mine works four days a week as a cab driver, and spends his remaining time working on two small businesses. The money from cab driving is terrible ($60/day, with a lot of variance), but it gives him time and freedom, and he enjoys cab-driving. But let's not limit this to "Ways to finance your start-up." Just, ways to pay your rent, long-term, while you work on whatever you like, regardless of financial return.
To put that another way, in the current marketplace, what kinds of program are so worthy of optimization that it's economically sensible to have a human spend several days hand-tuning machine language to squeeze out every CPU cycle?