It seems like Marian Rivera found her greatest rival in Pinoy Big Brother Double Up housemates as the reality show murdered both of her current shows last Sunday and Monday, January 3-4, 2009, based on AGB-Nielsen Mega Manila Survey. PBB Double Up took the top spot from Darna on Monday. PBB Double Up scored 35.1% while Darna 34.2. The Toni Gonzaga-hosted franchise also got the other Marian Rivera...