Ashlee Simpson wore a black bikini with white polka dots over the weekend while off on vacation in Cabo San Lucas with friends! On Friday, she lounged by the pool with a few girlfriends and her father, Joe Simpson. By yesterday, her sister Jessica Simpson and new boyfriend Vincent Piazza had joined in on the fun. The group sat down for lunch with Nicole Richie, who is also in Mexico enjoying a two piece-filled getaway. It was a big weekend for Vincent for another reason as well. Boardwalk Empire's season two premiere aired on HBO last night, and the show promises a lot more drama to come this year.