Waiting tables seems like a great one -- not a lot of "job security", but plenty of demand, so it should be fairly easy to match your amount of work to the amount of money you need to get back to work on more interesting things.
Firefighting seems to vary from city to city, but in many cities, it appears you can start as a firefighter with 6 mos. training, and the starting pay is decent ($55k in seattle, for example).
That brings up an interesting question, though: if you can make $55k/yr working 10 days out of every 30 in job x, are you less likely to succeed in your startup? How much of entrepreneurial success is motivated by need? (The existence of serial entrepreneurs would seem to indicate "not much".)
Firefighting seems to vary from city to city, but in many cities, it appears you can start as a firefighter with 6 mos. training, and the starting pay is decent ($55k in seattle, for example).
That brings up an interesting question, though: if you can make $55k/yr working 10 days out of every 30 in job x, are you less likely to succeed in your startup? How much of entrepreneurial success is motivated by need? (The existence of serial entrepreneurs would seem to indicate "not much".)