A hearty gang of 35 regular Seattle people (nonperformers), led by German artist Oliver Herring, are taking over the third floor of the downtown library. After interviewing and picking his volunteers, Herring writes tasks for each of them, and the all-day performance will begin with each person performing his or her artist-given task, such as "pick a cat hair or dog hair off somebody's sweater without somebody noticing and place it on somebody else." The 35 people will spend the rest of the day writing tasks for each other, creating a symphonic group portrait. (Central Library, 1000 Fourth Ave, 386-4636. 10 am–5:30 pm, free.)