This weekend, some of Hollywood's leading ladies will gather at producer Jennifer Klein's 12th annual Day of Indulgence party. What makes Amy Adams, Jennifer Garner and Jessica Biel regulars at the exclusive backyard bash? "It's a fun day of shopping and eating stuff that's bad for you," Rachel Bilson told us last year. Among the guilty pleasures that guests can look forward this year: pampering massages from Ona Spa, a shopping spread including must-haves from Henri Bendel, J Brand and Spanx, and sweet treats from Yummy Cupcakes, WannaHavaCookie and Auntie Fruf's Aahsome Fudge. The day will also end on a high note, with each guest taking home a custom made Nike suitcase stuffed with more than 70 pounds of freebies. The booty includes gift certificates for free stays and spa treatments from hotels like the Four Seasons Maui and the Encantado Resort, beauty must-haves from Votre Vu, Clarisonic and Topshop, plus buzzed-about items like Cosabella's super-sexy jean leggings, FujiFilm's Instax Mini 7 camera and the Fruitz Natural Frequency Technology watch, which helps improve sleep, relieve stress and fight the aging process. There's just one rule at this ultimate girls' day out--absolutely no boys allowed. "I heard a guy came one year and Jennifer kicked him out!" Kristen Bell reported.