Rihanna fired up the 54th Annual Grammy Awards in a black backless dress with a plunging neckline.  The blonde bombshell, who won the Grammy for Best Rap/Sung Collaboration for Kanye West’s “All of the Lights,” designed the outfit with Armani.  According to RiRi, the show-stopper was inspired by Michelle Pfeiffer in Scarface and is “simple, sexy, and gangsta at the same time.”  She made it a family affair, posing on the red carpet alongside her father Ronald and youngest brother Rajad