Teenage boys have decided that the sexiest thing in the world is ... smelling like an old dude. In the newest trend sweeping high schools and junior highs, boys from 13 to 18 are collecting vintage colognes, from as far back as the early '90s. They're stealing them from the dusty shelves of older relatives and scouring eBay and other resale sites, where used bottles of the old stuff are going for as much as $150. Big favorites include Le Male, which hit the market in 1995, and Acqua di Giò, which launched a year later. They're long gone from malls, but teens are lining up to find them. In fact, about 44% of boys ages 12 to 14 and 57% ages 15 to 17 use fragrance, according to market-research firm Mintel.