The world's third-richest man, Warren Buffett, turns 81 years old today. How does Buffett plan to celebrate the big 8-1? By working.

Buffett is 'doing what he loves most -- running Berkshire Hathaway,' according to a statement from the Oracle of Omaha's office.

We took a spin through one of our favorite Buffett biographies, Alice Schroeder's 'The Snowball,' to tease out a few other Buffett birthday highlights:

* For Buffett, Aug. 30 is actually a twin celebration. Buffett also was married on his birthday in 2006, to Astrid Menks. In case Buffett is still hunting for gifts, the fifth anniversary is considered the wood anniversary. May we suggest a yacht.

* As a birthday gift to his wife Susan, Buffett would give her 90 minutes in a store to 'race through and buy whatever she could grab,' Schroeder recounts in her book. Schroeder characterized the birthday gift as part of Buffett's habit of using money as a means of control. Susan Buffett also convinced her husband to give each of their children a million dollars once every five years on their birthdays, according to 'The Snowball.'

* At his 75th birthday party, Buffett had a white chocolate cake shaped as a $100 bill. He also played ping pong against nine-year-old champ Ariel Hsing -- and lost badly. (A table tennisbeating at the hands of a champion now is a regular fixture of the Berkshire Hathaway annual shareholder gathering.) A painter also was hired to teach Buffett and buddy Bill Gates the ins-and-outs of landscapepainting, Schroeder said.

* Buffett's 50th birthday was a black-tie affair at New York's Metropolitan Club with 500 of his richest friends and associates. Buffett's gathering featured his wife's band and a birthday cake shaped like a six-pack of Pepsi. (It was Buffett's favorite quaff before he became a shareholder in Coca-Cola and switched brands.)