The Motley Fool's CAPS investing service is another great way for investors to work together to beat the market. Among other features, CAPS lets users blog about their picks, investing strategies, market views, favorite rugby teams, or whatever floats their boat.

As CAPS blogging catches on, players add more great content every day. I've dug through the past week's posts to find some of CAPS' best insights. With room for only seven posts here, I can't possibly cover all of the great stuff in the CAPS blogosphere, so when you're done here, I highly recommend checking out some more.

The penny stock test
People just plain love penny stocks. Now, I say "people" and not "investors" because true investors tend to know better. Despite the fact that people lose money more often than not in this wildly volatile bunch, gamblers still repeat stories about the big scores, like Hanson Natural (NASDAQ:HANS), that crop up every now and again.

In a recent blog post, floridabuilder outlined a penny stock test he's conducting for 2008. He is adding 65 "penny" stocks -- including highly rated MRV Communications and Breakwater Resources -- to his CAPS portfolio and rating them all underperform. He expects that at least 75% of this group will underperform the S&P over the next year.

Top 10 rules for playing CAPS
Part of the beauty of CAPS is that it's not just a single thing -- to some it's a way to stack up their stock-picking prowess against others, to some it's a useful way to research stocks, and to some it's a game where they can try to rack up a huge score and climb to the No. 1 spot. And to others it's some combination of the above or something else entirely!

Sharing his experience on the game angle, SaintCroix has delivered a list of his top 10 rules for juicing your CAPS score.

What would the holiday season be without a video of a holiday party from the CAPS TV crew? The troupe's holiday song about CAPS brought tears to my eyes *sniff*.

Severe hedge fund unwinding continues
One of the top CAPS players, StatsGeek, has been watching odd developments in the market that he believes were driven by failing quantitative hedge funds that are trying to unwind many of their positions. Not only does he provide some interesting statistics, but also makes the prediction that quant funds will report dismal returns for December.

Do fools rush in?

It's not hard to understand why there is so much speculation about what Warren Buffett and his massive Berkshire Hathaway (NYSE:BRK-A) (NYSE:BRK-B) war chest are studying. After all, many consider Buffett the greatest living investor. After the financial press made a bunch of guesses that included Countrywide Financial (NYSE:CFC) and Bear Stearns (NYSE:BSC), CAPS All-Star JR10022 wonders why they can't just wait for some solid evidence before reporting.

Investing in banks
It's a scary time to consider investing in bank stocks like Citigroup (NYSE:C) and JPMorgan Chase (NYSE:JPM), but weiwentg thinks it could be a good time to do a little shopping in the industry. He cites an article by David Dreman that argues the same.

Guru accuracy
How good are stock market gurus? camistocks took a look at a report by CXO Advisory that examined how accurate many of the big-named gurus like Jim Cramer and Ken Fisher have been.

More CAPS Foolishness:

JPMorgan Chase and Bank of America are Income Investor recommendations. Berkshire is a recommendation in both Inside Value and Stock Advisor. In addition, The Motley Fool owns stock in Berkshire Hathaway. You can try any of the Fool's newsletters free for 30 days.

Fool contributor Matt Koppenheffer shares some thoughts of his own on his CAPS blog. He owns shares of Bank of America, but does not own shares of any of the other companies mentioned. The Fool's disclosure policy gives all glory to the Hypno Toad.