“A Bold Peace,” Old Chatham Quaker Meetinghouse, 539 County Route 13, Old Chatham. 6 p.m. potluck, 7 p.m. film. Free. In 1948, Costa Rica dismantled its military establishment and cultivated security relationships with other nations. It then invested in its people and created a society committed to peace. 518-7662992 or http://www.oldchathamquakers.org.
Cognitive and Immersive Systems Lab Research Demo, Experimental Media and Performing Arts Center, 110 8th St., Troy. 2 p.m. Free. Director Hui Su will introduce the vision of the lab, the progress made by the CISL team and several technical demonstrations.
End of Life Doula Class, William K. Sanford Town Library, 629 Albany Shaker Road, Colonie. 1:15 p.m. Free. An End of Life Doula cares for people at end of life by meeting their physical, emotional and spiritual needs. Registration required; http://www. colonielibrary.org.
Fall Festival, Elm Avenue Town Park, 261 Elm Ave., Delmar. 3 p.m. $7. Crafts, pumpkin decorating, a bounce house, pony rides. Leukemia & Lymphoma Society’s Light the Night Walk, Siena College, 515 Loudon Road, Loudonville. 6 p.m. Free. Raise money in support of cancer research and patient support services for those with leukemia, lymphoma, Hodgkin’s disease and myeloma.
MHACG 12th Annual Pumpkin Walk, Columbia Greene Community College, 4400 NY-23, Hudson. 4 p.m. $6. The Mental Health Association celebrates 60 years of community service with family entertainment and walk along a path of lit jacko’-lanterns. Proceeds support programs that serve children and families of Columbia and Greene counties. http://www.mhacg.org.