How do you reheat your popcorn...
...with good results? And, what's your favorite flavorings?
Actually, I don't bother. But if I was to, I think very briefly in the MW might do it, or in a hot uncovered pan on stovetop, tossed frequently to crisp and not burn. It's not so easy to do and get the crunchy good result from just popped corn. I don't mind room temp, slighty soggy popcorn. I don't usually have leftover popcorn, either.
Butter, salt and ancho chile powder for my current fav seasoning. Put the chile powder in the melted butter.