By Steve CrumA buncha stars gather in 1939 for an NBC radio broadcast, The Circle: (from left) Groucho Marx, Cary Grant, Lawrence Tibbett, Chico Marx, Ronald Colman (host), and (in front) Carole Lombard. The one hour show had different famous guests every week discussing current events and the arts in a round-table format. Sponsored by Kellogg’s, The Circle is considered one of radio’s celebrated failures, struggling for listeners from 1939-40. High pay for guests + low ratings tells the story.