GOSSIP GIRL Season 5 Episode 15 Crazy Stupid Love Sneak Peek : Season 5: “Crazy, Cupid, Love” : NATE THROWS A VALENTINE’S DAY BASH / ST. VINCENT PERFORMS — It’s Valentine’s Day on the Upper East Side and Blair (Leighton Meester) can’t resist playing cupid for someone she loves. Georgina (Michelle Trachtenberg) is intent on stirring up more drama, so she decides to crash Nate’s (Chace Crawford) Valentine’s Day party. Meanwhile, Serena (Blake Lively) is shocked by something she witnesses at the party. Penn Badgley, Ed Westwick, Kaylee DeFer, Kelly Rutherford and Matthew Settle also star. Matt Penn directed the episode written by Austin Winsberg (#515).