The Oracle of Maracoor. Gregory Maguire: author of Wicked and the new spinoff series, 7:30 p.m. at Page Hall 135 Western Avenue Downtown UAlbany Campus, Albany 12203

Indian Ladder Trail. Learn about the geological processes that shaped the rocky Helderberg Escarpment, and the ways that these rocks in turn shaped local history. The trail includes stairs, uneven surfaces, and low rock overhangs that require crouching to pass. 1 p.m. at Thacher State Park Visitor Center.

Caves & Karst. Starting with the karst display in the Visitor Center, participants will come to understand the development of Thacher Park's unique landscape. We will caravan to two additional areas in the park to observe their unique geology. 9:30 a.m. at Thacher State Park Visitor Center

Fall Foliage Walk. Come join us for a 2.6-mile hike through the Karner Barrens region of the preserve and take in the beautiful scenery of this rare ecosystem.  Reservations required. Visit www.AlbanyPineBush.org/events or call (518) 456-0655. at 11 a.m. at Karner Barrens trailhead (#1)

The Second Sunday Series at The Gallupville House.  Mark your calendars for a rich experience of Roots and Folk music that will have your feet moving at 3 p.m. at The Gallupville House 913 NY-443, Gallupville, 12073

Albany Fall Stamp and Postcard Show. Free admission and parking. Hosted by Fort Orange Stamp Club.  fortorangestampclub.org. 9:30 a.m. to 4 p.m. at  American Legion Hall 4 Everett Rd. Albany, 12205.

Gongs Along the Mohawk: A Sound Immersion.  Joining them in this immersive  journey is guitarist Scott Collins, whose exotic sounds are with tremendous passion and pyrotechnical velocity. 1 to 3 p.m. at Mabee Farm Historic Site 1100 Main Street Rotterdam Junction, 12150.

Slingerlands Living History Walking Tour. Participants will enjoy an afternoon walking tour in the hamlet of Slingerlands that features costumed actors portraying local notables like Congressman John I. Slingerland and engineer William H. Slingerland.  tickets can be purchased at https://slingerlandvault.eventbrite.com. from 2 to 3 p.m. at Slingerlands Fire Department, 1520 New Scotland Road.   

Voices of the Valley. A song cycle celebrating the Mohawk River Valley Songs by Morris & Rivers featuring Alice Sorensen & Dylan Perrillo.The suggested donation cost is $15. from 6 to 8 p.m. at Mabee Farm Historic Site 1100 Main Street Rotterdam Junction, 12150.

Writers' workshop. A community writers' workshop will have its first meeting. at 2 p.m. at Voorheesville Public Library 51 School Rd, Voorheesville, 12186,