Celebrities enjoy luxe Memorial Day weekend vacations

Serena Williams, Hilary Swank and Justin Timberlake are having a lot of fun.

— -- Some favorite celebrities were spotted kicking up their heels and taking in some fun on the Memorial Day holiday.

From Serena Williams attending the Monaco Formula One Grand Prix on Sunday, to Hilary Swank and Mariska Hargitay dancing in the Hamptons, these celebs seem to be having a really good time.

Neil Patrick Harris, Olivia Munn and Vanessa Hudgens also showed some holiday spirit.