Bill Gates offered a hilarious gift to Warren Buffett on his 90th birthday

Warren Buffett, the chairman and CEO of Berkshire Hathaway, attends an event in Washington, DC, in 2012. He is celebrating his 90th birthday this year.

Buffett was born in Omaha, Nebraska, on August 30, 1930. He was the only son of Laila and Howard Buffett. Howard was a US congressman.

A young Buffett, far left, is seen with his grandfather, Ernest, as well as his cousins and two sisters.

Laila Buffett poses with her three children — from left, Roberta, Warren and Doris.

Warren Buffett stands in front of his childhood home in Omaha.

Buffett teaches a class at the University of Nebraska-Omaha.

Buffett married his first wife, Susan, in 1952. They had three children together: Peter, Howard and Susan. The latter two are seen here with their parents.

Buffett and his wife pose at the beach with their three children.

Buffett poses for a photo in 1980.

Buffett testifies before a House subcommittee after the Salomon Brothers investment bank was caught in a treasury bond scandal in 1991. Buffett took over as the company’s chairman of the board to guide it out of troubles with the Federal Reserve System.

Buffett attends one of Berkshire’s annual shareholders meeting. Seated with him here are his daughter Susan, left, and his wife Susan. Buffett’s wife died in 2004.

Buffett arrives at an Omaha Dairy Queen to autograph books and chat with Berkshire Hathaway shareholders in 2002. Many people were in Omaha for Berkshire Hathaway’s annual shareholders meeting, which has been described as “the Woodstock of Capitalism.”

Buffett attends a GEICO ceremony in Trenton, New Jersey, in 2004.

Buffett joins California Gov. Arnold Schwarzenegger during a meeting of Wall Street investors in New York in 2004. Buffett advised Schwarzenegger’s gubernatorial campaign in 2003.

Buffett sits atop a fake bull at the Berkshire Hathaway annual meeting in 2006.

Buffett stacks his chips at a charity poker tournament in Omaha in 2006.

Buffett plays the ukulele with a band during the Berkshire Hathaway meeting in 2007. He learned the instrument decades ago.

Buffett stands in front of a portrait of himself, painted by Michael Israel, in 2008.

Buffett throws out the first pitch before a Kansas City Royals baseball game in 2008.

Buffett sits with Girl Scouts in Omaha in 2008.

Buffett uses a large paddle to play table tennis in 2010.

Buffett and Microsoft Chairman Bill Gates enjoy a meal together at the Hollywood Diner in Omaha in 2010. That year, the two launched The Giving Pledge, which encourages the world’s billionaires to dedicate the majority of their wealth to philanthropic causes.

Buffett is sworn in to testify before the Financial Crisis Inquiry Commission in 2010. The bipartisan committee was created by Congress to investigate the causes of the financial crisis.

President Barack Obama awards the Presidential Medal of Freedom to Buffett in 2011. “Today, we know Warren Buffett not only as one of the world’s richest men, but also one of the most admired and respected,” Obama said. “Unmoved by financial fads, he has doggedly sought out value, put his weight behind companies with promise and demonstrated that integrity isn’t just a good trait — it is good for business.”

Buffett is mobbed by journalists and shareholders during Berkshire Hathaway’s annual shareholders meeting in 2011.

Buffett talks with his son Peter before the start of the shareholders meeting in 2011.

Buffett poses for a photo in Omaha in 2012.

Buffett and his second wife, Astrid, arrive at the White House for a state dinner honoring British Prime Minister David Cameron in 2012. The next month, Buffett confirmed that he had been diagnosed with Stage 1 prostate cancer. He underwent radiation treatments and told Berkshire Hathaway shareholders that the cancer was “not remotely…