HAPPENIN’ OTSEGO for MONDAY, APRIL18 New York History Day Celebrated At Fenimore NYS HISTORY DAY — All day. Students from across the state battle (academically) for chance to compete at National History Day. Historians and educators judge student projects. Fenimore Art Museum, 5798 Rte 80, Cooperstown. Info, www.nyshistoryday.org SCOUT DINNER — 5-7 p.m. Cooperstown Troop 1254 Boy Scout Spaghetti Dinner fundraiser. Homemade sauce, sausage and meatballs, sides, beverage, dessert. Takeouts available. $10 adults; $8 ages 12 and under. Vet’s Club, 60 Main…