Why are you still alive? is the question doctors ask Ozzy Osbourne, the hard-rock singer and reality-TV star, who says he is now clean and sober after a lifetime of almost unimaginably bad habits. In June, he started two new ventures: undergoing the three-month process of genetic mapping (to help doctors learn why, indeed) and becoming a "health advice" columnist for London's Sunday Times. At various points in his life, the now-cholesterol-conscious, vegetarian Osbourne said he drank four bottles of cognac a day, smoked cigars like they were cigarettes, took 42 prescribed medications and many more "backstage" drugs that he could not even identify. Osbourne also has a Parkinson's-like genetic tremor, was once in a medically induced coma after an accident, and endured anti-rabies shots after famously biting into a bat on stage ("I thought it was a rubber toy").