Robin Ventura Park, also called Rotary Centennial Park, has two playgrounds, one for big kids and one for toddlers. There's a gazebo with three sidewalks that run downhill into it, making it fun for kids on skateboards. One kid was trying out his remote-control truck while we were there. A blue basketball court and some baseball fields are also here.

This is a nice, newish playground in a cookie-cutter development, and kids are bound to have fun.
If you're hungry, drive north on College Dr and then turn left on Betteravia Rd. On the left is Panera Bread which is attractive inside and has decent food. You pay up front and then find your own table. The food is ready fast which is good when you have kids.
For a park with a more wooded, natural feel, two ponds full of ducks, and several playgrounds, check out Waller Park, which we loved!
Kids love the Santa Maria Valley Discovery Museum, which has tons of activities to keep kids of all ages busy for an hour or two.
While in Santa Maria, check out beautiful Guadalupe Dunes where your kids can have fun leaping from up high. Also, a nice walk is Oso Flaco Lake where a pretty boardwalk leads over the lake past reeds and plenty of wildlife.

Directions

Robin Ventura Park is located at 2625 South College Dr, Santa Maria CA 93455.
Exit Highway 101 in Santa Maria at Santa Maria Way, and head northwest. Immediately turn right on College Drive. After several blocks, as soon as you pass Sunrise Drive, the park will be on your left. There is a large parking lot you can pull into.
Panera Bread, 540 East Betteravia Road, Santa Maria, call (805) 349-9800.‎

Click on map for interactive view