For "butter and sugar" sweet corn, I love Sandy's, located in the former Fjord Fisheries parking lot on River Rd. in Cos Cob. Really tasty, tho a bit overpriced (.60 an ear). She brings them in from Enfield.
I boil them no more that a couple of minutes. No need for butter, the kernels are so creamy. A little salt and pepper... and it's the quinessential taste of summer. Along with just picked beefstake tomatoes.
Other favorite farm stands? And how do you cook your corn on the cob?