Let's play a game. I'll say a word and you tell me the first thing that pops into your head.

Rule Breaker. For me, it's a blur -- a whirlwind winter into spring during which I made a small fortune then lost it. Y2k.

One stock rocket
I heard the term Rule Breaker in December 1999. I'd received a call from a science guy who had crossed to Wall Street's dark side, and on this particular day, he was salivating over a genome maverick based in my hometown. I bought the stock, which after a listless summer, heated up in the fall -- then Boom!

Before I knew it, this one flyer was my entire portfolio. And it was doubling weekly. News flow was positive, but this was something else. Turns out, a fellow named David Gardner at The Motley Fool had tapped the stock for a spot in his Rule Breaker real-money portfolio. At last -- I'd stumbled in front of a freight train.

It's not what you think
Rule Breakers and Rule Breaker investing is back, but it's not what you think. As fate would have it, David Gardner's path crossed mine, and when it did, David told me what a Rule Breaker was. Today, I'll pass that on to you.

David added AOL (NYSE:TWX), Amazon (NASDAQ:AMZN), and Amgen (NASDAQ:AMGN) to the original Rule Breaker portfolio between 1994 and 1998, and all left millionaires in their wake in the late 1990s. And all three were still way in the money at the market bottom.

But Rule Breakers are not just about tech. To hear it from David Gardner -- who, by the way, still owns all three -- it's low-tech Starbucks (NASDAQ:SBUX) that's the consummate Rule Breaker. Who else but Starbucks, he asks, sensed a need, met it, branded it, then spread it across the country?

But you know what really makes Starbucks a Rule Breaker? There's no second fiddle. I mean, where's the Pepsi to Starbucks' Coke? There isn't one. Starbucks is a Rule Breaker. If you bought the stock in the late 1990s, you're one, too. To this day, second best isn't even on the horizon.

Lesson 1: It's not all about tech. Exhibit A: Starbucks.

Martha, Martha, Martha
Still not low-tech enough? Back in 2002, the original Rule Breaker portfolio had been closed and David Gardner and his brother, Tom, launched Motley Fool Stock Advisor. But my impressions of The Motley Fool were still tangled with the human genome, Amazon, and the legend of David moving early into AOL and eBay (NASDAQ:EBAY). One word would change all that.

Martha. As in Martha Stewart. As in Martha Stewart Omnimedia (NYSE:MSO). Mark Hulbert is the watchdog of the investment newsletter industry and, if memory serves me, Hulbert mentioned that David was the only advisor recommending Martha Stewart to his readers. Small wonder -- Martha was a pariah.

That was November 2002. The stock was trading at $6.03. It's around $30 today. David closed out Martha Stewart in July 2004 at $9.05, a decision -- which he calls his worst in years -- that locked in a 50% gain. I should be so lucky. Here, I learned two lessons in one.

Lesson 2: Buy when there's blood in the streets -- especially if you have faith in the business, the financials, and most of all, the brand. Lesson 3: Let your winners run. Exhibit B: Martha Stewart.

Who's breaking the rules today?
How about Taser (NASDAQ:TASR)? That's right, I said Taser. Is the stock dramatically undervalued? No, but we're still talking about a market cap of less than $2 billion -- even after an 8,000% climb. Profit margins are generous at 27%, and cash flow from operations clocked in at around $13 million. Best of all, folks are scared stiff.

The fact is, beyond periods of real mania, most investors don't like to pay up for growth -- even unbridled growth. Unless you get in at the very bottom -- like David did with AOL in 1994 -- it is almost always painful to buy these stocks. Which is precisely why, in the right situation, buying these mavericks -- these Rule Breakers -- can turbocharge your returns.

Fair warning: Admit that you're eyeing Taser and people call you crazy. Is buying Taser a little risky? Darn right it is. Taser is no place for the emergency cash or the college fund. On the other hand, where's the Pepsi to Taser's Coke? Great growth stocks are never cheap, and there's a funny thing about people: They're often wrong.

Lesson 4: Don't listen to people. Exhibit C: Taser.

Are you one?
Rule Breaker. It's a blast from the past, but I'm real happy to hear it again. I'm one myself -- just ask the local authorities. And for the record, I rode my genome wonder all the way up and too much of the way back down. That lesson cost me.

Lesson 5: Be prepared to sell if the underlying story falls apart. Exhibit D: Celera Genomics.

So, what makes a Rule Breaker investor? I asked David Gardner that very question. "Simply, it's one who can embrace the contrary nature of paying up for great growth stocks." That's straight from the horse's mouth. Should you take David's word for it? I would.

Researching this column, I ran some numbers. Turns out, when David officially shuttered his real-money Rule Breaker portfolio, he'd managed a 20.1% annualized return. That was in mid-2002, after the bear market. Compare that to 9.1% for the S&P and 7.3% for the Nasdaq over the same period. Those are the kinds of results that made legends of Peter Lynch and Bill Miller, and rightfully so.

What to do now?
I don't claim that this is anything but an introduction. Aggressive growth investing is not for everyone -- certainly not for all of anyone's assets. But let's face it, the very best investments are the stocks of high-growth companies -- upstarts that come from nowhere and change our world. Companies like Amazon, AOL, and maybe even Taser.

The trick, of course, is spotting these companies and having the courage to take the plunge when you do. I don't have to tell you that this can be scary business. Isolation is deadly. If you'd rather not go it alone, David Gardner is offering a 30-day free trial to his brand new Motley Fool Rule Breakers advisory service. To find out more, or to take him up on this offer, simply click here.

Fool writer Paul Elliott owns Celera. The Motley Fool has a disclosure policy.