No matter how stoic you are, watching your stocks slide daily is unnerving.

At Motley Fool Hidden Gems, we haven't been immune to the sudden and severe haircuts Mr. Market has recently doled out. Since last September, we've had positions decrease 20%, 30% ... even 50%.

And frankly, we're excited about it.

Come again?
Sure, seeing those big red numbers can be painful, but we know that volatility presents great opportunities for patient investors to profit. That's particularly true when a company's fundamentals and business prospects haven't declined -- but its stock price has.

In a report called "How to Stop Worrying and Learn to Love Volatility" (PDF file), Lord Abbett senior economist Milton Ezrati showed how market volatility "can actually help build wealth over time, especially for longer-term investors."

According to Ezrati, regularly adding new money in a volatile market allows an investor to purchase more shares at cheaper prices, thus lowering the effective cost basis. Interestingly, Ezrati's findings hold true whether prices are rising or falling.

Of course, few investors feel like adding new money when the market seems to shift momentum at the drop of a hat -- but this is exactly the time to consider committing new capital.

Totally outrageous
Ready to commit that capital? You're in luck -- the market has put many fine companies on sale.

My Foolish colleague Tim Hanson recently highlighted a few stocks that he felt were outrageously cheap. Now, Tim's a great analyst and a deadeye three-point shooter (we play basketball after work), but I wasn't terribly outraged when I saw how cheap his stocks were.

These stocks are cheap
In fact, many good stocks are cheap right now. Celgene (NASDAQ:CELG) and sanofi-aventis (NYSE:SNY) recently hit 52-week lows. This is the cheapest that Diageo (NYSE:DEO), Southern Company (NYSE:SO), and Novartis (NYSE:NVS) have been in years. And these are all strong companies with killer brands.

Even supposedly "recession-resistant" stocks are feeling the pain. Tissue and diapers maker Kimberly-Clark (NYSE:KMB) just hit a five-year low.

But there's a reason
I think those are all fine companies, and at today's prices, there's a decent chance they'll go on to post market-beating returns. But there's a reason each of them has fallen, be it decreased consumer spending, competitive concerns, or general recession-fueled fears.

The key to exploiting market volatility is to find situations in which the share price has fallen, but the company's business fundamentals have remained unchanged (or even improved!). We have a few companies that fit that bill at Motley Fool Hidden Gems, including one candidate that looks ripe for new money now.

Going once ...
The company is Ritchie Bros. Auctioneers (NYSE:RBA), a Canadian company that specializes in selling industrial assets like tractors, trucks, and cranes. With more than 110 locations in 27 countries, Ritchie Bros. is the world's largest auctioneer of heavy-duty industrial equipment. And this is no fly-by-night operation -- the company has been facilitating farm equipment sales for about 50 years, and co-founder David Ritchie sits on the board and owns 8% of the company.

Of course the economic downturn will have an impact on sales, but demand for used equipment is far less sensitive than that for new machinery. While lesser competitors struggle, I expect well-capitalized Ritchie Bros. will continue to capture market share.

But although the company's prospects look healthy, the stock is trading about one-third off its 52-week high!

Ritchie Bros. is exactly the type of opportunity we look for at Hidden Gems: It's a small cap with a strong balance sheet, shareholder-friendly management, and underappreciated growth potential. Better yet, the company's share price has been beaten down, even though its prospects continue to look bright.

We have quite a few companies that meet these criteria on our radar, and some of them are looking pretty darn cheap. If you'd like to start profiting from the recent market volatility, click here to take a free 30-day trial of the Hidden Gems service. As always, there is no obligation to subscribe.

This article was first published Feb. 5, 2008. It has been updated.

Rich Greifner has learned to love flaxseed oil, volatility, and the bomb. Rich does not own shares of any company mentioned in this article. Ritchie Bros. Auctioneers is a Hidden Gems recommendation. Diageo, Kimberly Clark, and Southern Company are Income Investor recommendations. Novartis is a Global Gains pick. The Fool has a disclosure policy.