New Hits Needed; Apply to NPR

“Ask Me Another,” which began broadcasts on some NPR stations in May (but not in New York), is part of a new land rush for precious public-radio weekend airtime. Developed on modest budgets, many of the newcomers are aimed at a decidedly younger audience than currently listens to NPR; some aim for diverse listeners. All face a big hurdle: limited open time slots and, some would argue, a risk-averse public-radio culture, where time-tested audience and money generators make it challenging for new shows to thrive.