What: A day of free family-friendly activities to celebrate Columbia's 40th birthday.

Where: Merriweather Post Pavilion, Columbia Town Center.

When: Gates open at noon.

Entry: Parking on Merriweather's lots and entry to the pavilion is free. No glass containers or alcohol can be brought in. Organizers plan to hold the event if it rains.

Information: www.columbia40.com.

Highlights

Noon to 5:30 p.m.: Picnicking is encouraged on the Merriweather grounds, and concession stands will be open. Howard County General Hospital will hold a health fair. There will be music on four smaller stages, strolling entertainers and a play area with a Moon Bounce and a climbing wall.

6 p.m.: The original Young Columbians perform.

7 p.m.: The Baltimore Symphony Orchestra performs.