Las Vegas
Old Las Vegas
Old Mormon Fort State Historic Park - A restored fort stands on the site where Las Vegas began, near a creek with grass and meadows ("las vegas" means meadows in Spanish). In 1855, Mormon pioneers built an adobe fort; a decade later a ranch was developed which included a store and blacksmith shop for travelers.
Kids can wander around the adobe buildings, very atmospheric of an earlier era.  The creek is flowing again, and there are picnic tables in the shade. On Saturdays are programs, such as pioneer activities, scavenger hunts. Closed Mondays.
Heritage Park - Next door to the fort is Heritage Park, a park just for kids, with a large playground, grass to run around, and more picnic tables.
Las Vegas Natural History Museum - The Wild Nevada Gallery has a super life-size diorama of Nevada wildlife, such as Bighorn sheep, mountain lions, golden eagles, Gila monsters, elk, ravens, desert tortoises, coyotes. Learn about the animals that burrow under the ground to escape the desert heat - burrowing owl, snakes, mice, lizards and tortoises. Touch an elk antler, fur pelt, rattlesnake and Gila monster skins. Smell sagebrush and listen to the sounds of eagle, bobcat, raven, quail and rattlesnake. Open daily.
Discovery Children's Museum - The museum has plenty of hands-on activities for kids of all ages. Desert Discovery is an exhibit for kids under 5, bigger kids can play a laser harp, be a radio DJ, explore a virtual city. There are also daily arts and crafts activities, and demonstrations. Closed Monday.
Tip: All these museums and the park are within one block of each other, in the northern part of the city, but you'll need a car to drive there.