A big bang for your buck. Easy to make with only two easy to find ingredients.
Step 1: What You Need
Electric sparklers. And a whole roll of electrical tape.
Step 2: Wrap the Sparklers
Hold the sparklers in an even row. Let one from the middle stick out about two inches. Wrap them up from top to bottom, making sure to use the entire roll of tape.
Step 3: Light 'em Up!
Light the sparkler that sticks out. Drop it and run. There's not a big fire type explosion but it sure sounds like one. Sorry there's no pictures of it blowing up.