In large bowl combine the oats, rice crispy's, brown sugar, and cinamen. Stir together the syrup and oil; stir into oat mixture. Spread evenly in a greased 15x10x1-inch baking pan. Bake in a 300 degree oven for 30 to 35 minutes or until lightly browned, stirring after 20 min.
Spread on a large piece of foil to cool. Break into clumps. Store in an airtight container for up to one week.(or, store in freezer bags and freeze for up to 2 months.)