All Weekend

Annual Bellmore Family Street Festival - Bellmore. Weekend long fair at the Bellmore Long Island Railroad Station. Arts, crafts, jewelry, food, vendors, games, rides, animals and more. Cost: Free admission.

Maritime Festival - Greenport. At East End Seaport Museum and Marine Foundation. Classic, Ice and Small Boats displayed in Mitchell Park and Village Marina, Watercraft Viewing, Tours and Sailaways, Maritime Museum, Railroad Museum, Carousel,Old Greenport Jail, Stirling Historical Society, Village of Greenport Shops and Restaurants, Fireboat Museum Tours and more. Cost: Free admission.

Queens County Fair - Floral Park. Held at the Queens County Farm Museum, this traditional county fair features blue ribbon competitions in livestock, produce, home crafts, arts and crafts, and more. Enjoy the Amazing Maize Maze, visit the Con Edison Ecology Booth where you can adopt-a-worm for your home compost bin, get great planting tips, recycling ideas, and enjoy free crafts for kids. Carnival rides, corn-husking contests and more. Cost: $9/adults; children $5 (ages 12 and under are free.)

For the Kids of East Islip Annual Carnival - East Islip. Weekend-long festival. Free admission, games, rides, food costs additional.

The Butterfly House - St. James. At the Sweetbriar Nature Center visitors will learn about the various stages of the butterfly's life cycle, view butterflies, children will become detectives searching for clues of the butterfly life cycle and color a butterfly to take home. Cost: $5, $3 seniors and children ages 11 and under.

Saturday, September 20

Fall Family Fun Festival - Westbury. At Hicks Nurseries, this festival includes children’s workshops, lawn and garden care seminars, pumpkin contests, hay rides, planting demos and more. Cost: Free admission.

Explorer Family Backpacks - Hempstead. At Hofstra University Museum, pick up a backpack and discover the beauty of the world's cultures through specific works displayed in the gallery, create your own keepsake artworks to bring home, for children ages 5-10. Cost: Free.

Arts in the Plaza - Long Beach. At Kennedy Plaza, check out local artwork. Free kids art stations. Cost: Free admission.

Yoga at the Farm - Cutchogue. At Sang Lee Farms. Mat yoga in the field with a fresh pressed juice after. Cost: $15/person.

Fit4Mom Nassau County Stroller Strides - Seaford. At Cedar Creek Park. Daily stroller walking mommy & me exercise program. Cost: First class is free; paid packages available thereafter.

Train a Seal, Kiss a Sea Lion at the Long Island Aquarium - Riverhead. At the Long Island Aquarium & Exhibition Center

Science Saturday at the Long Island Science Center - Riverhead. Kids can learn and play at the Long Island Science Center with over 30 hands-on exhibits. The center is open from 11am to 4pm. Cost: $5 per person.

Craft for Kids at Lakeshore Learning Store -  New Hyde Park. At the Lakeshore Learning Store. Cost: Free.

Grown Up & Me Yoga (Ages 3-5) -  Bellmore. Mommy or Daddy and Me yoga at Emerge Yoga & Wellness. Cost: $15.

Friendship Bracelet Making Demo Class -  Mineola. Learn about making lanyard jewelry at this demonstration class hosted by The Lanyard Ladies. Cost: Free.

Parents Night Out - Smithtown. Lil' Builders hosts a drop-off program for kids. Snack, dinner, beverages, craft, Legos and more. Cost: $35/child, $25/siblings.

Sunday, September 21

Long Island Apple Festival - East Setauket. At the Sherwood-Jayne Farm, this festival highlights all things apples. From foods to games and cooking demonstrations and more. Cost: Free.

Cow Harbor Day - Northport. A traditional, annual festival celebrating the history of the Village of Northport. Cost: Free admission.

Fall Family Carnival - Old Westbury. The Sid Jacobson JCC is hosting its annual fall festival with rides, games and other attractions. Cost: Free admission.

Sunday Seatuck Family Nature Club - Islip. Birds, trees and seasonal things. Cost: Free

LEGO Club at CMEE - Bridgehampton. Children's Museum of the East End, Bridgehampton, 10am. Children can construct works of art using the thousands of Legos at the Museum. Cost: Free with admission. NOTE: CMEE will be closed after 5pm on Sunday, August 31 and all day Monday, Sept. 1 - Friday, Sept. 5 for their annual fall clean up.

Mommy/Daddy Me Anti-Gravity Yoga - Bellmore. Have your little one explore the Anti-Gravity hammocks while building basic motor skills. All kids AGY classes are structured to introduce basic life skills and build confidence in a light-hearted way while having fun. Cost: $20.

Family Sundays at the Nassau County Museum of Art - Roslyn. Each Sunday, Nassau County Museum of Art offers a 1pm docent-led family walk-through of the exhibition and supervised art activities for the whole family beginning at 1:30pm. Special family-friendly gallery guides of the main exhibition are in the galleries.