By Geoffrey James, recently featured on Inc.com

It’s been said that “when life hands you lemons, make lemonade.” That’s thinking too small.

A better approach is to turn the lemons into a business plan.

Here are three examples of people who, when hit by personal tragedy, turned it into an opportunity for growth.

Josh Opperman: Broken Promise, Better Price

Opperman came home one day to an empty Manhattan apartment to find his girlfriend gone, with only an engagement ring left behind. Ouch.

As Josh, heartbroken, sat in his home, staring at the ring, he consoled himself with the fact that at least he could return the ring and get his money back. And since the ring cost around $10,000, he anticipated a fair chunk of consolation.

Unfortunately, when he went to the jeweler, he discovered that–despite the fact they could obviously resell the ring for another $10,000–they’d give him only 35% of the purchase price!

Talk about life handing you a lemon.

Opperman realized, however, that his personal disaster was actually an opportunity in disguise.

He founded the website I Do … Now I Don’t, which buys engagement rings from broken relationships and resells them to suitors looking for a good deal. Opperman says he’s now making around 1,200 sales a year.

Payman Taei: Using Bed Rest to Launch a Business

In 2000, Taei was in his senior year at University of Maryland studying to be a biologist, anticipating an active life of field research. One day, after going to the doctor about what seemed like a minor complaint, he learned he had Crohn’s disease.

As Taei quickly learned, Crohn’s can turn life into a living hell. Bedridden and coughing, he was unable to attend classes.  The idea of field work–hiking, camping, gathering specimens–was as unlikely now as a trip to the moon and back.

However, the one good thing about being stuck in bed is that you’ve got plenty of time on your hands. Taei used that time to fiddle around on a computer and learn about digital art. His work got noticed, and soon he was in demand as a website developer.

Today, Taei is the CEO of HindSite Interactive, one of Maryland’s leading design and development firms; in 2011 it was named one of the top U.S. design firms by the International Business Times. He went from a man who was seemingly losing control of his life to become a man who helps entrepreneurs and businesses be successful on the Web.

I can’t finish this post without mentioning Mitchell, although I’m certain that many of you already know about him.

It’s probably not fair to characterize what happened to Mitchell as life handing him a lemon. He experienced two huge disasters in quick succession: a motorcycle accident that left his skin burned and shredded, then a plane crash that paralyzed him.

Many people, facing such disasters, would become bitter and angry. Mitchell was neither.

Instead, he’s used his life experience to show that even seemingly impossible setbacks can’t keep somebody from success, if they are truly determined.

Over the years, he’s founded a $65 million company and been a two-term mayor, a congressional nominee, a radio host and television personality, a published author, and a Speakers Hall of Fame inductee.

Mitchell went so far beyond the “lemonade” concept that it’s not on the same scale at all. He’s become a truly transformational role model. I defy anyone who hears him speak to leave the auditorium believing in insurmountable obstacles.

So there you have it: three examples where personal tragedy was transformed, through innovation, commitment, and plain old guts, into major business success.