All Weekend

Greek Festival on the Harbor - Port Washington. 12pm-10pm at North Hempstead Beach Park. Cost: Free admission.

Festival by the Sea - Lido Beach. 11am-6:30pm. Live concerts, great food, giant inflatables, children's shows, clam eating and rib eating contests, sand sculptures, pony rides, circus acts, biathlon, cool science, Disney Road Crew, games and giveaways, petting zoo and more. Cost: Free admission, free parking.

The Long Island Fair - Old Bethpage. 10am-5pm. Every fall, Old Bethpage Village Restoration hosts The Long Island Fair. Held on the re-created historic Mineola Fairgrounds, the fair combines the best of old time county fairs with prize winning competitions. Thousands of exhibits and a variety of entertainment such as jugglers, mimes, puppet shows, magic acts, and traditional dancing. Cost: Adults - $12, Children (5 to 12) and Seniors - $8. Children under age 5 are free.

Fall Garden and Harvest Festival - Great River. At Bayard Cutting Arboretum. 10am-4pm. Activities, demonstrations, tours, garden displays, produce and plants, soil testing, pumpkins for painting ($2), face painting, wool spinning and weaving, model train exhibit, Manor House tours ($8). Cost: Free admission.

Otto the Ghost's Animated Story - Westbury. Six animatronic scenes run continuously during store hours at Hicks Nursery and have read along story cards. Cost: Free admission.

Lego Building Contest & Exhibit - Stony Brook. Original Lego creations on display at the Stony Brook Village Center. Cost: $4/person admission.

Saturday, September 27

Family Arts Festival - Garden City. 10am-4pm. This free Family Arts Festival at Museum Row in Garden City will kick off Arts Month and feature the parade at Museum Row, food trucks, a performance stage, a scavenger hunt for kids, raffles and more. Cost: Free admission.

St. Margaret's Fall Fair - Plainview. Bounce house, games, vendors, food, antiques, raffles and prizes. 10am-4pm. Cost: Free admission.

Magic of Alexo - Oakdale. At CM Performing Arts Center. Alexo’s stage show offers a tour de force of the world of magic. His mind-blowing, audience-engaging presentations create a memorable experience for all involved. Experience everything from sleight of hand, comedy magic, escape artistry and bizarre stunts. Cost: $12/person.

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.

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.

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.

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.

Sunday, September 28

Village Day Fall Festival - Sands Point. 12-5pm at the Sands Point Preserve. Outdoor activities for guests of all ages, including a petting zoo, hayrides around the Great Lawn, pony rides overlooking the Long Island Sound, pumpkin painting for budding artists and a Green Grocer with wonderful items, including award-winning artisanal cheeses, fresh baked goods, apple cider, and famous Horman pickles. Cost: $20/car or $10 with annual pass.

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.