Ask HN: You're a recent grad that's working full time on your startup. How?

I'm curious as to how the recent grad crowd works full-time on their startup. I've read multiple comments over the last few weeks from people that do this, so I have to be nosy and ask the obvious question - how do you do this? Personally, after graduation I will need to get a "real" job to pay for expenses, housing, food, etc. Ideally, of course your startup makes money, but it's obvious that comes with no guarantee or time frame. Are the bulk of these fresh grad full-timers somehow independently wealthy, do they just get by with part-time jobs, or am I missing something entirely?

Let me know, thanks.