If you mean fresh as in still having the husk as in summer corn, then just peel back the husk, removing the silk threads (completely), put several pats of soft butter on replace the husks, tie with butchers string, place in a flat pan (to catch any melted butter) and roast in the oven in a hot oven ... at least 400 degrees F (we're in the U.S.) for about 30 to 45 minutes.
If it's fresh sans husks, place in aliminimum (I told you we're in the U.S., didn't I), add a tablespoon of water, some butter mixed with about a tablespoon of sugar per ear, wrap tightly and place in the same hot oven for about the same time...
Enjoy!