Residents can get into the spirit of St. Patrick’s Day by taking part in “Celebrate the Green,” the annual weeklong merchant event in the downtown that is organized by the town’s Event Planning Committee. The week was set to kick off with special activities on Saturday. Through next Sunday participating businesses — those displaying a shamrock in their windows — are offering specials and a raffle. Meanwhile, Ty Burr, an author and Boston Globe film critic, will kick off the town’s annual Sweetser Lecture Series. Burr will speak on “Fame Games: How 100 Years of Movie Stardom and Celebrity Have Changed American Society” on Wednesday at 7:30 p.m. at Wakefield High School. Tickets are $10 per lecture or $25 for the series and may be purchased at the door or in advance. For more information, call 781-246-5320.