Photo by: Aaron Friedman.

Warren Buffett is no stranger to making money. As the head of Berkshire Hathaway (BRK.A -0.28%) (BRK.B -0.68%), his sole goal is to discover ways to make money with his right hand man, Charlie Munger.

Ever since Warren Buffett first entered the investment industry in his early 20s, he has participated in a number of odd investments, many of which most investors have never heard of.

Here are three of the weirdest:

1. Cocoa beans
In the earliest years of his time in investment management, Warren Buffett took part in a special situation whereby he could acquire cocoa beans at a discount to their actual market value. He bought shares of Rockwood & Co., an obscure Brooklyn-based chocolates company that was liquidating one of its businesses.

The company traded for $34 per share. However, it promised to exchange $36 of cocoa bean warehouse certificates for each share of stock. Cocoa beans were up some 1,000%, and Rockwood & Co. wanted to cash out at that high price, according to his 1988 annual shareholder's letter.

The obvious solution was to buy Rockwood & Co. shares for $34, sell them back to the company for $36 in cocoa beans, and then sell the cocoa beans for $36. The process netted an instantaneous return of about 6%. Considering the transaction could be done in less than a week, it worked out to a sky-high annualized return.

2. Odd-ball insurance policies
Berkshire Hathaway is one of the biggest insurers in the world, so it often writes policies that other insurance companies can't touch. In 2003, Pepsi ran a promotional contest called the Pepsi Billion Dollar Sweepstakes.

The company offered a chance to win $1 billion, which would have been the biggest sweepstakes in history. In total, 100 people were selected for the game show, which aired on WB.

Of course, Pepsi couldn't exactly afford the risk of actually losing $1 billion. So, Berkshire Hathaway insured the risk at the cost of less than $10 million. In all, 100 people had a 1-in-1 million chance at winning a $1 billion. No one won. Berkshire Hathaway took its premium and enjoyed the proceeds.

That's hardly the start to Warren Buffett's weird dice rolls. He said in 2009 to a group of Harvard students that Berkshire Hathaway underwrote a two-year life insurance policy for Mike Tyson. He wanted an exclusion against women shooting him, but that was non-negotiable.

3. Silver
Buffett's spent many years talking about how he dislikes gold as an investment. But starting in 1997, he began to amass 37% of the world's known silver reserves for Berkshire Hathaway at prices ranging from as low as $4 to $6.

Unfortunately for Buffett, this is one area where he made a mistake. He sold somewhere around 2006, at prices around $10-$12 per ounce. Silver went on to rally much higher, striking nearly $50 per ounce in April 2011 as measured by the Silver ETF (SLV -0.36%).

To be fair, Buffett didn't lose money on his speculative silver play, but his investment did come with a big opportunity cost. From 1997 to 2006, Berkshire Hathaway nearly tripled. His own company's stock would have been a better investment than silver.