Check out this great NASA video showing a coronal mass ejection—a burst of plasma thrown off the surface of the Sun—from several different perspectives. It happened on August 31 and it's really gorgeous. It's also rather huge, as far as these things go. Luckily, it wasn't pointed directly at Earth. Coronal mass ejections can affect our planet's magnetic field. There's a risk of large ones screwing with everything from our electric grid to radio waves.

Read more about coronal mass ejections on Wikipedia