What can you accelerate using a vacuum? How about a ping pong ball to several hundred miles per hour? The vacuum cannon evaculates the air from a PVC tube. Both ends of the tube are sealed using sheets of aluminized mylar and inside is a ping pong ball. After the air is evacvuated, you puncture the mylar film closest to the ping pong ball. As the air rushes back in, it creates a force on the ping pong ball. Since the air pressure is 101.3 kP and the ping pong ball has a low mass of three grams, the ball's acceleration can exceed 1,000 g's. By the time the ping pong ball reaches the end of the tube, it bursts through the other mylar film cap with a loud bang.
The kinetic energy of the ping pong ball is equal to the energy required to evacuate the PVC, minus losses due to friction and drag. Still, a ping pong ball capable of flying through an aluminum can is mightly impressive.
You can see a video of my vacuum cannon on my YouTube channel