9 hobbies highly successful people practice in their spare time

The most successful people know there is more to life than simply eating, sleeping, and working.

Everyone needs to enjoy some downtime every now and then, and making the most of your free time by taking up a hobby can even help make you more successful.

Playing a musical instrument, for example, can stimulate your creativity, analytical skills, and fine motor skills.

For a little inspiration, here are the hobbies of nine highly successful people:

Meryl Streep knits

The award-winning actress says she loves to knit, and she's even said to have hand-knitted the shawl she wore in the movie 'Doubt.'

Streep admits that she spends much of her time on set knitting and finds the hobby to be therapeutic: 'For me it was a place to gather my thoughts and understand the contemplative (life) ... it's a sort of clearing out place.'

In fact, tons of celebrities, especially actors who have plenty of time to kill on set between takes, love to spend their free time knitting. The list includes Julia Roberts, Ryan Gosling, and Christina Hendricks.

Kate Middleton colours

In recent years, adult colouring books have taken the world by storm, with titles like Johana Basford's 'Secret Garden' topping Amazon's bestselling books list.

According to her husband, Prince William, even the the Duchess of Cambridge is susceptible to the allure of colouring.

Proponents for the emerging trend suggest colouring as an alternative to meditation and mindfulness practices, saying the practice can help reduce stress and organise one's thoughts.

Ray Dalio practices Transcendental Meditation

As Business Insider's Rich Feloni reports, the Bridgewater Associates founder has said the practice is 'the single biggest influence' on his life.

Dalio began practicing Transcendental Meditation in 1969 as a college student, after seeing that it was taught it to the Beatles. Since then, he has brought the practice to his employees, and waves of Wall Street bankers and investors are signing up for lessons.

Tom Hanks collects vintage typewriters

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As Business Insider previously reported, the actor and filmmaker has been collecting vintage typewriters since 1978, and he uses one every day because he loves the sound, feeling, and permanence that comes with typing on one.

'Everything you type on a typewriter sounds grand, the words forming in mini-explosions of SHOOK SHOOK SHOOK. A thank-you note resonates with the same heft as a literary masterpiece,' he writes for The New York Times.

Sergey Brin is an adrenaline junkie

In his spare time, the Google cofounder likes to push his body to the limit in any way he can. This includes roller hockey, ultimate Frisbee, gymnastics, skydiving, and high-flying trapeze.

Steve Wozniak plays polo ... on a Segway

Apparently Segway polo is a thing, and the Apple cofounder is the namesake of one of the sport's major world tournaments, Woz Challenge Cup, the World Cup of Segway polo. The game is played in four quarters, and five players on each team try to get a rubber ball past the opponent's goalie.

'Segway polo is the one thing I will block off my calendar for,' Wozniak tells Quartz.

Tim Gunn soaks up art

The 'Project Runway' cohost and mentor told The New York Times that he spends every Sunday at the Metropolitan Museum -- 'I stay there basically until the museum is about to close.'

He dons a suit -- 'I want to prepare myself properly' -- and walks through Central Park to get there.

'I'm a huge lover of art,' he explained. 'I go to the Greek and Roman galleries first. I'll choose different objects to fixate upon. A trip to the Met can be very emotional. There are paintings there that just lift me off the ground. I feel buoyant.'

He then heads to the Balcony Lounge for a glass or two of wine and tea sandwiches and pulls out his iPad to research what he's just seen. 'I have become insatiable on the topic of ancient Rome.'

Warren Buffet plays the ukulele

According to Forbes, the Berkshire Hathaway CEO's love for the ukulele spans decades.

Buffett often uses his musical talent for good and has donated instruments and lessons to children's clubs in Omaha and given performances for charity.

Angelina Jolie collects weapons

As previously reported on Business Insider, Jolie is another Hollywood actor with a unique hobby: She collects knives with her family.

Jolie tells W Magazine that her mum introduced her to daggers when she was a kid, and that she has passed this hobby on to her son, Maddox. She says the knife blades she gives him are dulled so he can't hurt himself, and that their dagger purchases are always 'accompanied by discussions about violence.'

In another interview with Conan O'Brien, Jolie shows off her skills with a butterfly knife and explains that her fascination with weapons comes from the history behind them: 'There's just something beautiful about them.'