HAPPENIN’ OTSEGO for SATURDAY, AUGUST 19 Celebrate The Haudenosaunee HAUDENOSAUNEE—2-5 p.m. Celebrate Native America. Learn the history of the Haudenosaunee, participate in traditional social dances, and find unique items by hand crafters. Free. Lucy B. Hamilton Amphitheater, Fenimore Art Museum, 5798 State Highway 80, Cooperstown. (607) 547-1400 or visit https://fenimoreartmuseum.org/ RIVER CLEAN-UP—8 a.m. to noon. Susquehanna River Clean-up. Remove trash from the river, take pictures, provide refreshments, or help with first aid if needed. All jobs available. Sign-up required. Cleaning from the…