Fun trick at bonfires at the beach, as well as at Christmas parties in the fireplace. For a really big one, take a dixie (or small styro) cup, fill it half full of coffee mate, tape a good sized firecracker (m-80) inside the cup with the fuse sticking out, and toss it into the fire. Get BACK! When the thing pops, the powder atomizes and ignites like a cloud of gasoline. Nice ball of flame. Huge noise. Scares the fuck out of everyone. Bring three, and don't tell anyone, ever, what happened. Just look as surprised as they are when it happens again.
