From the unconventional and awe-inspiring to the hilarious and heartwarming, here's a look at some of the most interesting photos, videos and stories that have our newsroom talking today. What's capturing your attention, filling your inbox and cluttering your Facebook/Twitter feed? Tweet us the stories you're talking about using #InstantIndex, or email us at ABC.WorldNews@abc.com, and they could appear on "World News."

What's the Best Way to Eat a Burger Without Making a Mess? Researchers in Japan used their engineering and dentistry knowledge to figure out the best way to eat a burger without making a mess. For four months, they ran 3-D scans and discovered that most people eat burgers with four fingers on top and thumbs on bottom. But the most ergonomically efficient way to eat it is with pinkies and thumbs on bottom and just three fingers on top.

Olivia Newton John Going to Las Vegas Olivia Newton John will be headlining at the Flamingo Hotel and Casino in Las Vegas starting April 8. She will perform 45 shows at the Donny and Marie Showroom through the summer. She promises to perform everything from "Xanadu" to the "Grease" classics.

(FilmMagic/Getty Images)

Marvin Gaye Passport Found in Vintage Album A Motown fan in Detroit scored big time when he bought some vintage Marvin Gaye vinyls from an estate sale and the singer's passport fell out of one of the LPs. It was issued in 1964 shortly after Gaye signed his first big record deal. Experts at the "Antiques Roadshow" say it could be worth $20,000. The Detroit fan paid just 50 cents for the album.

Little Girl's Scathing Yet Adorable Critique of Lego Goes Viral A little girl's letter to toymaker Lego critiquing its attitude toward women is causing a stir on social media after a sociology blog shared it on Twitter. TheSocietyPages.org posted a photo of the letter, which was written by 7-year-old Charlotte Benjamin and submitted to the publication by her parents. In the hand-written message, Charlotte expresses her disappointment that Lego does not have many products that target girls. "I don't like that there are more Lego boy people and barely any Lego girls," she wrote. She also criticizes the way the company portrays women in their attire and activities. She notes that all the boy products are blue while girls are pink, and that while boy characters engage in exciting adventures females are limited to traditional gender roles.