Serena Williams and Jennifer Lawrence Partied This Week

Photo: Getty Images; BFA

Celebrities celebrated Halloween with and without costumes this year: Serena Williams wore a full-on ‘80s Jazzercise getup, Lindsay Lohan was a convincing Harley Quinn, and Aziz Ansari chose a plain black suit (a little disappointing!).

There were plenty of other parties throughout the week, too. Zoë Saldana and all three Olsen sisters appeared at a gala hosted by Gucci and the Los Angeles County Museum of Art honoring director Kathryn Bigelow and the installation artist Robert Irwin. The Weeknd winked at a camera (and by proxy, us). Singers, songwriters, and country stars partied in Nashville before Beyoncé and the Dixie Chicks dominated the CMA Awards.

Click ahead to see party pics from this week.