Found this recipe for red, white, and blue bark over at this site. Looks easy enough, as long as you use good chocolate, like the Guittard Dark pastilles that I wrote about recently. Be careful of putting them outdoors in heat, they will soften and melt for sure!
Step 1: Prepare pan
Line cookie pan with parchment paper.
Step 2: Melt Candy
Melt red, white and blue Candy Melts following package instructions.
Step 3: Make Candy Bark
Spoon candy into prepared pan distributing colors randomly. Tap pan on counter to remove air bubbles. With spoon or butter knife, marble candy in pan. Sprinkle with cinnamon drop or peppermint crunch sprinkles. Chill until firm, about 10 minutes. Remove parchment from pan; break candy into smaller serving pieces.