Katy Perry spent yesterday afternoon in her bikini at Raging Waters in San Dimas, CA, with a group of friends. Katy is enjoying some downtime after wrapping a worldwide tour to promote her movie, Part of Me, which most recently took her to Brazil. John Mayer and Katy Perry have been spotted out together on a couple of dates recently, and went to a house party together on Saturday night, but he didn't join her at the water park. Neither she nor John have commented on their relationship, which is one of Katy's first since her split from Russell Brand. She was also linked to the guitarist of Florence + the Machine earlier this year, but the pair apparently cooled off early this Summer.