POP quiz: What do venture capitalists, Bill Gates and major investment banks have in common?

They are all making large bets on ethanol.

Some of those wagers have already paid off, Bloomberg Markets reports. The $66 million that Morgan Stanley paid for Aventine Renewable Energy, a maker of ethanol, three years ago is ''worth about $750 million, according to a company filing, as runaway oil prices spur an ethanol boom.''

That trend could continue because a provision in last year's Energy Policy Act requires refiners to increase significantly their biofuel use by 2012, guaranteeing ethanol distillers a market for the first time, Joe Carroll writes.

''Today, the U.S. consumes 4.4 billion gallons of ethanol, or the equivalent of 3 percent of all gasoline used,'' he writes. ''The federal mandate will boost that figure to almost 5 percent by 2012.''

This explains why in April, Cascade Investment, Mr. Gates's investment vehicle, spent $84 million to become the biggest investor in Pacific Ethanol, the magazine writes.

With gasoline continuing to cost about $3 a gallon, articles in business magazines detailing ways readers can profit from soaring energy prices are well on the way to replacing ones about how to make money in real estate. (See the next item for another example.)

But as with real estate, commodity markets can cool as well.

''For distillers to expand rapidly after 2012, the price of ethanol will have to be competitive with gasoline,'' Mr. Carroll writes. ''Last year, even with oil reaching a then record $70.85 a barrel, it cost refiners $1.61 to make a gallon of gasoline -- less than the $1.80 it cost to buy a gallon of ethanol.''

SWEET -- The white crystalline substance you put into your coffee isn't an energy play you would necessarily think of, but as Trader Monthly puts it ''sugar futures are the Pop Rocks of the commodities world right now.''

And, yes, ethanol is the reason.

''Because Brazil -- which fills more than half of the world's exported sugar bowl -- has one of the most advanced ethanol industries in the world, the South American giant is now diverting a significant portion of its sugar crop into ethanol production,'' Jonathan Hoenig writes. ''This, in turn has pushed up prices.''

The way sugar trades is what has caught the attention of commodity traders.

''While most futures contracts can rise or fall only so much in a given session before automatic lock-limits kick in, sugar has no such curbs,'' Mr. Hoenig writes.

''Moreover, it carries one of the lowest margin requirements in the business. Some $1,540 in margin money controls a contract equivalent to roughly $19,000 worth of sugar.''

Which means you can make -- or lose -- a lot of money very quickly.

EMPTY SEATS -- ''High ticket prices, artists' demand for huge upfront payments and some stars' decisions to play overly large venues have led to a rocky start'' for summer concert sales, Rolling Stone reports.

Madonna, Pearl Jam and Dave Matthews are still drawing well, but they are the exception, Steve Knopper writes, noting, for example, that tours by Ashlee Simpson and Bruce Springsteen are not doing well.

The Dixie Chicks ''are in the biggest trouble,'' he wrote. They have postponed sales for four shows, although a spokesman for the band quoted in the article blamed scheduling issues. ''Many shows are soft,'' says Alex Hodges, executive vice president of the Houses of Blues. ''Is it the effects of gas prices or high ticket prices or the lack of stellar shows? Probably all of the above.''

FINAL TAKE -- ''Ever call in sick so you could take care of an ill pet?'' Cosmopolitan asks. The answer, it seems, is a resounding ''yes.''

''Eighty-five percent of pet owners admit to having told their bosses that they have come down with something but actually spent their day tending to their animal companion,'' the magazine reports.

This gives new meaning to the dog days of summer. PAUL B. BROWN