bill gates mugshot
Everybody knows Bill Gates -- Microsoft cofounder and longtime CEO, former richest man in the world (now #2), and named Time's Man of the Year in 2005 for his work with the Gates Foundation. 

But fewer people know the other cofounder, Paul Allen. (He's the guy in the bottom right.)

He's a regular topic of conversation in Seattle; not so in New York, Silicon Valley, or beyond.

Odd since Forbes lists as Allen the 37th richest person in the world, with $13.5 billion.

With his billions, he's invested in a lot of tech companies, but he's also had a fascinating life.

While a lot of billionaires stay dead serious about their business, and dig into other serious realms like politics and philanthropy, Allen has never been afraid to have fun with his fortune.