No, *don't* let them sit around! :) The sooner you cook them after harvest, the better they taste. That's the only real reason to grow your own corn, since it's so cheap in the store. Corn really loses flavor fast, esp. at room temperature, but even in the refrigerator.

Corn will be ready about 21 days after you see 20% of corn silks in your patch. Some corn varieties will hold their flavor for up to a week if in the refrigerator.

My Dad always said that you boil the water first then you go pick the corn. And run rather than walk back to the house.

Individual ears are ready for harvest when the silk is shriveled and brown at the outside ends.

This first picture is corn not ready: http://extension.missouri.edu/explore/images/g06390photo01.jpg

And this ear is ready: http://www.gardenaction.co.uk/images/sweetcorn-ripe-tassles.jpg

Sweet corn and tomatoes are two veggies that you can only get at their best when you grow them yourself. So enjoy!