Stupidity is contagious. It gets us all from time to time. Even respectable companies can catch it. As I do every week, let's take a look at five dumb financial events this week that may make your head spin.

1. The HP weigh
A little notoriety has spared former CEO Mark Hurd from the sinking ship that Hewlett-Packard (NYSE: HPQ) has become.

The latest stumble under Leo Apotheker's brief but tumultuous run at the helm came on Tuesday, when a leaked memo forced HP into delivering bad news to its shareholders earlier than expected.

Apotheker's grim memo to senior executives warned of near-term weakness and the need to scale back hiring and nix profitless transactions. Once the missive was smoked out, the computing giant bumped up its disappointing quarterly report. True to the memo, HP's guidance for the balance of the year is not as rosy as analysts were targeting.

Well played, Hurd.

2. Wall ton
What the blazes is wrong with Wal-Mart (NYSE: WMT)? The world's largest retailer posted its eighth consecutive quarter of negative same-store sales.

Keep in mind that inflation isn't baked into comps. In other words, even escalating food prices haven't been enough to stop the bleeding registers at the discount department store chain.

The obvious argument is that folks that traded down to Wal-Mart during the recession have gone back to less embarrassing shopping haunts, but I don't buy that. There's a fundamental shift in the way we buy things these days. Most media formats -- CDs, DVDs, books -- are going digital. Online shopping is growing in popularity. If someone's just going to Wal-Mart for apparel and groceries, it makes sense to go to a more fashionable retailer and hit the more convenient grocery store closer to home.

Wal-Mart's comparisons should get easier at this point -- if I'm wrong. The current quarter already has two years of sandbagged results, so it should be a breeze to deliver positive same-store sales. If this streak somehow stretches to nine quarters, run and never look back.

3. Chinese indigestion
A fast-growing restaurant chain in China seemed like a no-brainer IPO last year. Reality has presented an entirely different menu.

Shares of Country Style Cooking Restaurant Chain (Nasdaq: CCSC) tumbled 30% yesterday after posting problematic quarterly results.

Revenue may have climbed a little better than 40%, but same-store sales growth of 4.4% means that the concept couldn't keep pace with inflation at the individual unit level.

The news gets worse for CSC as you walk down the income statement. With the notable exception of food costs, meaty line items including wages, rent, utility, and SG&A expenses all outpaced the eatery's top-line growth. CSC's founding team was enough to grow the concept and take it public, but it may be time for more seasoned operators to grow CSC outside of its home turf.

4. Putting the "owe" in IPO
It's not an Internet bubble, but LinkedIn (NYSE: LNKD) sure has a lot of helium.

Shares of the white-collar social network traded as high as $122.70 in yesterday's debut, giving the company a whopping $11.6 billion market cap temporarily. It's a lofty price tag for a site that was barely profitable on just $243.1 million in revenue last year.

I don't mind chasing growth stocks that seem overpriced to those limited by rear-view mirror thinking, but the high beams don't look so good here either.

The bullish camp argues that LinkedIn will change the way jobs are filled in the future. I suggest that it'll be just as easy for Facebook to add a work-oriented layer to its base that is six times larger -- and far more engaged -- if it truly becomes that lucrative.

5. Only the Sony lonely
After weeks of a self-imposed outage, Sony (NYSE: SNE) finally let its gamers go back online.

Maybe those nerdy Sony lifeguards should've checked for sharks in the water before giving revelers the "all clear" to get back into the water.

The blogosphere quickly pointed out a security exploit where a nefarious hacker can change a gamer's passwords by simply entering the correct email address and birth date. The problem is that this was exactly what hackers were able to swipe on more than 100 million Sony gaming network members last month! It's why Sony had to take down the network for several weeks.

Sony quickly took down the password reset feature that was being hacked, but it's another embarrassing knock on Sony just as it's teaming up with mobile partner Ericsson (Nasdaq: ERIC) to put out the PlayStation-esque Xperia Play smartphone.

Which of these five moves do you think is the dumbest? Share your thoughts in the comment box below.

The Motley Fool owns shares of Wal-Mart. Motley Fool newsletter services have recommended Wal-Mart and Country Style Cooking, as well as a diagonal call position in Wal-Mart Stores. Try any of our Foolish newsletter services free for 30 days. We Fools may not all hold the same opinions, but we all believe that considering a diverse range of insights makes us better investors. The Motley Fool has a disclosure policy.

Longtime Fool contributor Rick Munarriz is a fan of dumb and smart business moves. Investors can learn plenty from both. He does not own shares in any of the stocks in this story, except for Country Style Cooking. Rick is also part of the Rule Breakers newsletter research team, seeking out tomorrow's ultimate growth stocks a day early.