ST. MARTIN'S DAY CELEBRATION: Enjoy festive German music, make traditional paper lanterns, learn St. Martin's Day songs. Parade around Rice Park, then enjoy more music, coffee or cocoa and sample authentic German treats. You're encouraged to bring clothing donations for Joseph's Coat, which provides free clothes and services for the needy. 4-6 p.m. Free. Landmark Center, 75 W. 5th St., St. Paul. 651-292-3233. www.landmarkcenter.org.

MINNESOTA SKI, SNOWBOARD AND SKATEBOARD EXPO: Nearly 100 exhibitors providing the latest products and information. Local, regional and western ski areas are represented. A huge preseason sale on equipment and apparel, with special deals on helmets. Skateboard contest hosted by 3rd Lair. 10 a.m.-6 p.m. $12. Minneapolis Convention Center, 1301 2nd Av. S., Mpls. 612-335-6000. www.onthesnow.com/bewi.

GO GREEN EXPO: Energy-efficient and environmentally friendly products, conservation, recycling, home building, presentations, panel discussions and more. 10 a.m.-5 p.m. $5-$10. Minneapolis Convention Center, 1301 2nd Av. S., Mpls. 612-335-6000. www.gogreenexpo.com.

TITANIC - THE ARTIFACT EXHIBITION: Recovered artifacts from the great ship, which struck an iceberg and sank on its maiden voyage in 1912. Exhibit includes reconstructions of parts of the ship, and a large piece of the original hull. 9:30 a.m.-5 p.m. $8-$29. Science Museum of Minnesota, 120 W. Kellogg Blvd., St. Paul. 651-221-9444. www.smm.org.

NICKELODEON UNIVERSE: Seven-acre indoor theme park with 30 rides and attractions. 10:30 a.m.-7:30 p.m. Unlimited-ride wristband, $29.95. Mall of America, Interstate 494 and Cedar Av. S., Bloomington. www.nickelodeonuniverse.com.