CORN on the COB is best eaten the day that it's picked ~ or the next day at least.
If you get it at the grocery store and the husks seem dry or wilted, it may be a few days old, so this is what I do to "plump" up the kernels and get them a little sweeter again (before sticking into foil packets and putting them on the BBQ grill)
Shuck them and lay them in a dish that has water with honey (depending on how many ears of corn, you may need up to 1/3 cup honey) whisked into the water. There should be enough water to cover the corn about 3/4 way up. Lay the corn in there ~ and turn it over every 1/2 hour or so before cooking.