A real mixed bag for you today. First, we've been meaning to get to this: NASCAR driver Jeremy Mayfield reportedly tested positive for methamphetamines some two weeks back. A time-honored tradition Mayfield was following, to be sure, but most interesting to us for now is his excuse: That his positive test result was triggered by his taking a combination of an over-the-counter allergy medication, Claritin-D, as well as Adderall, a presciption amphetamine used to treat Attention Deficit