Naomi Watts and Liev Schreiber are the latest celebrities to step out in costume today! They hit the streets of NYC with their kids, Sasha and Samuel, though Samuel sported regular clothes for the spooky holiday. Naomi was in a full clown outfit while Liev was draped in a grim reaper robe and Sasha in a samurai suit. There were plenty of celebrities in Halloween costumes over the weekend, especially at Kate Hudson's annual party in LA. Nicole Richie went as Jennifer Lopez, Jessica Alba was a witch, and Ali Larter channeled a bumblebee. Stay tuned for all the cute celebrity kid costumes that will be on display during tonight's trick-or-treating fun!