Curtis Jackson, better known as the rapper 50 Cent, has become an investor in Gunnar Optiks. He first became interested in the company based on billboards. While Gunnar wanted an endorsement deal, instead Jackson invested in the company. This is promising: He invested in Glaceau, the maker of Vitamin Water, which then sold to Coca-Cola in 2007 for $4.1 billion. Jackson made about $100 million off that deal.