I found this recipe at Taste of Home and I often make it at Christmas time to give away as gifts. It is easy to make, and is very good. Just be sure that there are no unpopped kernals in the popcorn, or you could break a tooth biting into it! It actually stays somewhat soft, but you still want to be careful.
8 quarts popped popcorn
1 cup butter
1/2 cup light corn syrup
1 (9-oz) pkg red hot cinnamon candies*
Place popcorn in a large bowl, making sure there are no unpopped kernals in there. Set aside.
In a saucepan, combine the butter, corn syrup and candies. Bring to a boil over medium heat, stirring constantly. Boil for 5 minutes, stirring occasionally. Pour over the popcorn and mix until as thoroughly coated as you can get it. Spread into 2 greased jelly roll pans and bake at 250 degrees for 1 hour, stirring every 15 minutes. Remove from oven and spread popcorn out onto waxed paper to cool. Break apart and store in airtight containers or plastic bags.
*In case you don't know what these are, click on the link above. You should be able to find them in the candy aisle at the grocery store. If you can't find them there, check the baking aisle.