Like any living institution, this year's Inc. 500 is both reassuringly familiar and utterly surprising. The familiar bits could be anticipated by any faithful reader of Inc.: They are the themes of guts, determination, and endurance that somehow find their way into most stories of entrepreneurial success.

For sheer Job-like endurance, it's hard to beat online marketing company Advice Interactive Group, No. 328 on this year's Inc. 500. For one awful stretch in 2011, CEO Bernadette Coleman and her husband Thomas, the company's CFO, alternated between the bedside of their son Michael, in a coma after a Florida car crash, and their offices in Dallas, where half the staff had suddenly quit. "We were fighting for our son's life and for our company," says Coleman. Michael recovered, thankfully, and the company is doing just fine as well: This is its third consecutive year on the 500.

The surprising bit about the 500--and it always surprises me, even though I know it's coming--is the sheer variety of the paths our entrepreneurs take to success. The kinds of companies that break out evolve with the economy, of course: This year there are far more social media and far fewer computer hardware businesses than there were, say, six years ago. But what doesn't change is the fearsome creativity unleashed by American entrepreneurship. Our list includes CoolMiniOrNot, No. 310, which, in a cute reverse-technology twist, makes board games that play like video games; Bowlmor AMF, No. 423, a bowling alley empire, the ultimate in retro chic; and Boxman Studios, No. 120, which grew 3,074.1 percent since 2010 by turning old shipping containers into traveling party spaces for events. You can't make this stuff up--except that every year 500 inspiring entrepreneurs seem to do just that.

The most astounding story, though, may be kids' tablet maker Fuhu, which landed at the top of the list for the second year in a row, with 158,956.9 percent growth. Back-to-back No. 1's just don't happen. (Well, to be precise, they have happened only one other time in the list's 33-year history.) Fuhu executives Robb Fujioka and Jim Mitchell pulled it off by rapidly multiplying product lines and distribution channels, and by driving their workforce as hard as they drive themselves. But--as senior editor Lindsay Blakely deftly points out in her profile of Fuhu, breakneck growth and hard-driving leadership create their own challenges. The delicate and emotionally complicated transition of one's baby from spindly startup to scaled-up enterprise is one that many, if not all, Inc. 500 honorees will eventually have to face. But it's a good problem to have.