Summertime at the Cove
The Cove is one of Newton's best-kept secrets. I've been going there since the early 1970s. The only way to get there is via a bunch of obscure side roads in Auburndale without any signs, or by canoe.
They've removed all the old kids' equipment, including the Yellow Submarine and the infamous spinning wheel of nausea, but they have some new wooden structures that are just as fun.
The Cove is great for anyone who likes the outdoors.You can play on the playground equipment, play in the fields (if there's no baseball game going on), feed the ducks (not the Canadian geese!), have a cookout under the trees (you might have to reserve the grills, anyone know for sure?) and take nature walks -- there's a network of paths that go along the river toward Waltham's Island neighborhood, the Marriott, and Lyons Field in Auburndale.
At one time back in the 70s and 80s they had ice skating at the Cove in the wintertime, but I don't think the City of Newton oversees that anymore.