8 large or 80 small marshmallows
1/2 cup butter
1/2 cup brown sugar
1/2 cup uncooked popcorn, popped

Melt butter and brown sugar in the microwave on HIGH. Add marshmallows and cook on HIGH until melted together, stirring after each minute. Cool only until just melted for sticky popcorn; cool approximately 3 minutes for crunchy. Pour over popcorn and mix well.

Variations
Chocolate: Use 1/2 cup sugar and 2 tablespoons unsweetened cocoa instead of brown sugar.

Cinnamon: Use a 12 ounce bag of red hots and 4 tablespoons cornstarch. Do not use any other ingredients. Cook as above.