Two Miami radio-show hosts known for playing outrageous pranks on the air scored perhaps the most outlandish one of them all Monday: They called Venezuelan President Hugo Chávez and got him to believe he was talking to Fidel Castro.''We still can't believe it,'' said Enrique Santos, co-host of El Vacilón de la Mañana, (The Morning Hijinks), on WXDJ-FM El Zol 95.7, a Spanish-language salsa station. ``He fell for it.''The joke was part of a segment called Fidel Te Llama or ''Fidel's Calling You,'' in which Santos and co-host, Joe Ferrero, call various people and play snippets of a controversial...