Planning an affordable weekend? These four organizer-listed outings offer free admission. Details were checked October 29; recheck the linked listings before travelling.

Friday, October 30: The National Arts Centre’s Day of the Dead celebration starts at 6 p.m. at Peter A. Herrndorf Place, 1 Elgin Street. Expect an altar tour and an all-ages workshop. No tickets are required.

Saturday, October 31: Rideau Hall hosts family Halloween activities from 10 a.m. to noon, with a free concert from 11 a.m. Enter through the Princess Anne Entrance. Security screening applies; concert seating is first come, first served.

Saturday, October 31: Diefenbunker activities at the entrance and Blast Tunnel run 10 a.m.–1 p.m., 3929 Carp Road. No booking is needed. Museum admission and the indoor scavenger hunt require separate paid tickets.

Saturday, October 31: Main library, 120 Metcalfe Street, screens Demons at 1 p.m. and Suspiria at 3 p.m. Both are free, drop-in screenings for mature audiences.

Organizer listings: NAC celebration; Rideau Hall; Diefenbunker; Library screenings.