I'm always looking for a good deal, whether that means buying an extra box of Golden Grahams when they're on sale, or pouncing on undervalued stocks. The idea that anybody would sell a stock for less than it's worth may seem silly, but an allegory from legendary value investor Ben Graham (no relation to the cereal) tells us how to watch for these situations.

In The Intelligent Investor, Graham introduces readers to a wacky chap named Mr. Market. He pays you house calls on a daily basis, offering to sell you interests in businesses he owns, or to buy from you interests in businesses you own. Sometimes, Mr. Market will show up at your door very excited, ready to pay premium prices for your holdings. At other times, he'll be inconsolably depressed about the future, and will offer to sell you what he has for as low as pennies on the dollar.

To find some of the stocks that Mr. Market is depressed about, I've turned once again to The Motley Fool's CAPS investor community. Each of the companies below had received a five-star rating (the highest) from our community of investors just 30 days ago:

Stock

30-Day Return

1-Year Return

Current CAPS Rating
(out of 5 stars)

Transocean (NYSE: RIG)

(17.9%)

3.2%

****

Aluminum Corp of China (NYSE: ACH)

(7.4%)

23.4%

*****

Activision Blizzard (Nasdaq: ATVI)

(6.5%)

4.3%

****

Data from Motley Fool CAPS as of May 3.

As the table shows, these stocks are all still very well-regarded by the CAPS community, despite their underperformance over the past month. While these are not formal recommendations, let's see whether opportunity could be staring us in the face.

Aluminum Corp of China
Last month, Aluminum Corp of China, also known as Chalco, reported a solid profit for its first quarter, following a long downswing driven by the global recession. For the first quarter, the company earned $92 million on $4.3 billion in revenue. That was a big improvement on its $2 billion in revenue and $276 million loss in last year's first quarter.

The earnings weren't enough to reverse the stock's decline, though. About a week before Chalco's report, fellow aluminum producer Alcoa (NYSE: AA) took the air out of the industry by reporting sales that missed analyst's targets. Though the rest of the market has continued rallying on the back of strong earnings elsewhere, both Alcoa and Chalco have continued to slump.

Of course, we can't lay all the blame for the drop on Alcoa. Concerns over the sustainability of China's growth have also led to a broad slide on Hong Kong's Hang Seng index. The increased reserve requirements for banks imposed Monday by China's central bank aren't likely to turn things around, either.

But CAPS members remain hot on China, particularly when it comes to natural resources and infrastructure. That means they're also still hot on Chalco.

Activision Blizzard
It's been an interesting month for the top dog in the video game industry. In mid-April, news broke that two former Activision executives -- who were responsible for the Call of Duty: Modern Warfare franchise, one of Activision's most successful game series -- had formed a new game studio and signed a publishing and distribution deal with Activision archrival Electronic Arts (Nasdaq: ERTS). The whole thing is a bit of a sordid tale, with the developers at Activision's throat and vice-versa.

Then, a few days later, Activision made the supposedly positive announcement that its first quarter would shake out better than the company originally thought. The market greeted that news with yawns, further rselling off the stock. Of course, as my fellow Fool Rick Munarriz pointed out, there wasn't much to be excited about, anyway.

But a lot of what we're talking about -- particularly when it comes to earnings -- are short-term issues. Over the longer term, analysts seem to think that the company can put up annual growth near 15% per year. Nearly 6,000 CAPS members are convinced that the stock will manage to outpace the rest of the market.

Transocean
If there were ever a potential opportunity for contrarian investing, it'd be when the companies you're considering played a part in a major man-made disaster.

In case you haven't read much beyond the headlines of the disaster unfolding in the Gulf of Mexico, there are three companies besides the actual oil companies that also have a hand in what's going on. First and foremost, we've got Transocean, which was hired to drill the well.

Cameron International (NYSE: CAM) manufactured the blowout preventer which, well ... didn't exactly prevent a blowout. And Halliburton (NYSE: HAL) is also in on this mess, because it was a subcontractor on the project when the explosion took place.

The stocks of all three of these companies have taken their lumps, but Transocean has clearly absorbed the brunt of investors' disappointment. But the stock's steep decline could also mean opportunity knocking -- at least according to several CAPS members.

While Transocean's stock has picked up quite a few underperform ratings thanks to the Gulf disaster, many CAPS members have stuck with the company in hopes that it can ride out this storm. Uclayoda87 gave the stock a thumbs-up on Monday, saying:

Oil slicks will eventually go away, but the demand for oil products in the US won't. In the short-term this company will fall hard, but with $5+ dollar per gallon of gas coming, it is likely that oil production will not be hindered for too long.

I've given all three of these stocks a thumbs-up in my CAPS portfolio. But here's the important question: What do you think? Head over to CAPS and share your thoughts with the other 160,000-plus members currently part of the community.

These stocks may rebound, but are they on their way to being home runs? My fellow Fool Jordan DiPietro seems to think these three stocks are.

Activision Blizzard and Electronic Arts are Motley Fool Stock Advisor picks. Motley Fool Options has recommended a synthetic long position on Activision Blizzard. The Fool owns shares of Activision Blizzard. Try any of our Foolish newsletters today, free for 30 days. The Motley Fool has a disclosure policy.

Fool contributor Matt Koppenheffer does not own shares of any of the companies mentioned. You can check out what Matt likes in CAPS by visiting his CAPS portfolio or you can connect with Matt on Twitter @KoppTheFool. The Fool's disclosure policy offers you one Schrute buck for reading this far.