Line an 11x17 baking sheet with the saltine crackers. Place in a single layer. Set aside
Preheat oven to 350 degrees.
In a saucepan over medium heat, mix together brown sugar and butter. Bring to a boil, stirring frequently. Boil for 3 minutes, not stirring.
Pour mixture over the crackers. Quickly spread, so it covers all of the crackers.
Place in the oven and bake for 7 minutes.
Remove and sprinkle chocolate chips evenly over toffee. Place back in the oven (oven heat turned off), for 5 minutes.
Remove from oven. Using an off set spatula spread the melted chocolate evenly over the toffee. Sprinkle immediately with sprinkles or M&M's.
Let harden completely before slicing.
Store in an air tight container.