You know that summer is in full swing when polo returns to Bridgehampton. On Saturday, hostess Brooke Shields, decked out in Ralph Lauren Purple Label, mingled with Lola Schnabel, Stella Keitel, and star player Nacho Figueras at the season opener. But the weekend action wasn't all pony-related. Alvin Valley celebrated his birthday with an in-store soirée in Southampton, while Valentino's Carlos Souza showed off his new jewelry line, Most Wanted Design, nearby at Julia Koch's house. The previous afternoon, Cristina Greeven Cuomo, Samantha Boardman, and Dayssi Olarte de Kanavos welcomed Alex Kramer, Adelina Wong Ettelson, and Emilia Fanjul Pfeifler to a Chloé trunk show at Saks. The talk of the party? The Chloé Betty bags on the arms of all the hostesses.