Discover Girl Scouts, for girls in grades K-3 and parents/caregivers, 6 p.m. at Van Buren Community Center.

Local Writers at the Library at Presque Isle Public Library, 6-8 p.m. Featuring Marie Sims, Virginia White, Alice Bolstridge and others. Free and open to public. FMI: 768-5827.

Annual trick-or-treat night at UMPI for children 12 and under, 6-7 p.m. in Park and Merriman halls. Student Activities Office and Residential Life will sponsor a haunted house 6-8 p.m. […]

Farmers' market, 4-7 p.m. in the Brookside Inn parking lot. FMI: 370-0379.