A full rundown of the ones you don't want to miss. If you can't get in, look for photos the next day on our party page.
What: Balenciaga Paris launch
Where: Barneys New York, 660 Madison Ave. at 61st St.
When: September 8, 6 p.m.–8 p.m.
Who: Barneys is celebrating the American release of Balenciaga Paris, the designer's archival retrospective. Expect every big fashion editor and, of course, Nicolas Ghesquière.
Why to go: Best chance to spot the brilliant French designer.
What: Mario Testino and Carine Roitfeld party
Where: Gramercy Park Hotel, 2 Lexington Ave., nr. 21st St.
When: September 9, 10 p.m.–midnight
Who: Fashion's young swans Julie Roitfeld, Margarita Missoni, and Bee Schaffer are being toasted by Ms. French Vogue and the famed lensman.
Why to go: Best guest list. The girls are inviting all of their pretty young (and famous) friends.
What: Marc Jacobs after-party
Where: Top-secret locale
When: September 11
Who: The M.J. after-bash is the week's most guarded and coveted invite. Film royalty (Sofia Coppola) and rock stars (last season, Kim Gordon and Karen O made appearances) make it a standout.
Why to go: Best party. Period.
What: Narciso Rodriguez after-party
Where: Asia de Cuba, 237 Madison Ave., nr. 37th St.
When: September 12
Who: What started as an intimate dinner for the designer ballooned to include top editors, favorite models, and friends of Narciso. Look out for the Condé crew, Solange, Daria, Gemma, and the rest of the designer's model army.
Why to go: Prettiest dinner party.
What: Chloé and New Yorkers for Children party
Where: Chloé boutique, 850 Madison Ave., at 70th St.
When: September 13
Who: No Fashion Week is complete without a gathering of the uptown social set. Marisa Noel Brown, Lydia Fenet, Zani Gugelmann, and Alexandra Lind Rose host this debutante ball for Tracy, the new Chloé bag.
Why to go: Best gift bag, but that's about it.
What: Satine party
Where: Marquee, 289 Tenth Ave., nr. 26th St.
When: September 13, 9 p.m.
Who: L.A. boutique Satine is partying for the sake of partying. Kim Gordon hosts, and the guest list boasts Lindsay Lohan, the Olsens, Nicole Richie, Kate Bosworth, and more of the L.A. crowd.
Why to go: Convenient L.A.-bashing.