If you happen to find yourself at Marblehead Neck, turn right and go deep; you might just find yourself in warbler fairyland. 360 degrees of black & white, blackpoll, pine, magnolia, northern parula, Canada, and a bunch more. Add red-eyed vireo and blue-headed vireo and a flicker displaying its golden shaft, and you might find yourself glued to the same spot on the boardwalk for an hour. Just watch out for the birds zooming past your head.
Given their foraging behavior and their persistent high-pitched chatter, the black & whites are the most apparent (and easiest to photograph).
Photo-wise, most of my afternoon was like the following:
Or look closely Canada warbler, I do believe, if you can find it...