Nov. 21 & 22. Show and sale of thousands of tropical and hardy orchids, orchid-growing supplies, and related items. Also, free talks and demos by orchid growers on the “Basics of Growing Orchids” (11 a.m.) and “How to Repot or Mount Your Orchid” (1:30 p.m.) on both days. 10 a.m.–4 p.m., U-M Matthaei Botanical Gardens, 1800 N. Dixboro Rd. Free admission; metered parking. (734) 647–7600, annarbororchidsociety.org.