Have you ever owned a tweener?

A tweener, dear Fool, is like your pal Chuck. Still a great athlete, Chuck no longer rules the hardwood with his 40-inch vertical leap. He's become what we sports addicts call a gamer. He passes more. He's developed a nice shot from the corner. And although he doesn't dunk as much, or as spectacularly, as he did, Chuck is still a force in the paint.

What we fans don't know is how long Chuck will be in the starting lineup. Chiseled veteran Abe has a wicked hook shot that won't quit. And Larry, the little guard whose hip-shaking moves smoke defenders, has the makings of a superstar. Both are vying to cut into Chuck's minutes on the floor.

In Foolish parlance: Chuck is a tweener, Abe is a Rule Maker, and Larry is a Rule Breaker.

Growing up is hard to do
The stock market has plenty of Chucks. They'll either create billion-dollar fortunes as they come to dominate industries, as Cisco (NASDAQ:CSCO), Microsoft, and Google have done, or they'll be destroyed in the process, as Gateway was.

Therein lies the problem. Investing in tweeners can be dangerous andexceptionally profitable -- the trick is picking your winners well, as David Gardner has. He produced nine years of 20% average returns hunting for misunderstood multibaggers in the making. His team at Motley Fool Rule Breakers continues the tradition today.

Let's have the list
You, too, can join the effort, thanks to Motley Fool CAPS. Each week we'll use the database to find three-star stocks that are expected to boost earnings by at least 15% annually over the next five years. Here is today's list:

Company

CAPS Rating

5-Year Growth Estimate

Harmony Gold Mining (NYSE:HMY)

***

63.5%

JA Solar (NASDAQ:JASO)

***

37.5%

Interwoven (NASDAQ:IWOV)

***

27.5%

Allegiant Travel (NASDAQ:ALGT)

***

18.3%

AU Optronics (NYSE:AUO)

***

15%

Sources: Motley Fool CAPS, Yahoo! Finance

Keep in mind that this isn't a list of recommendations. I offer these stocks as candidates for further research. But of these five, it's Interwoven that interests me most.

Why? Like Documentum, which was acquired by data storage specialist EMC (NYSE:EMC) some years ago, Interwoven specializes in storing and retrieving documents that aren't easily codified into a database but nonetheless contain important data. (Email and contracts come to mind.)

What's more, trading for a 1.05 PEG ratio, the stock is potentially cheap. And returns on capital, while not excellent, have been steadily rising in recent quarters -- a bullish sign.

Intrigued? Do your own due diligence and then check in with thousands of other investors at CAPS. And, if you'd like, add your own commentary. You'll be helping your fellow Fools and testing your ideas at the same time. Click here to get started now; the service is 100% free.

See you back here next week for five more growth stocks that seem stuck in the middle.