Park Slope’s 5th Avenue is hosting a holiday festival this Saturday, complete with a tree lighting, Santa Claus and carolers. The fun begins with a tree lighting at 6:30 pm at the corner of 5th Avenue and 3rd Street (in front of S’Nice). There will be free hot chocolate, marshmallows, cookies, brownies and popcorn during the outdoor festivities, which will last until 9 pm. Puppetry Arts and NY Kids Club will present puppet performances and games, and singer-songwriter Amy Miles and carolers from Opera on Tap will perform. And there will be specials and sales at shops and restaurants all along 5th Avenue in honor of Small Business Saturday.