Since its very first version, iTunes has had a visualizer, a built-in light show that you can use to play trippy animations while you listen to music. (Grateful Dead music not required.) You may not have ever used it, or even know it’s there, but it’s a lot of fun to turn on while listening to music, if you’re not working on your Mac (or if you just want to take a break). Altered states might make it even more interesting, but it’s a great way to have some captivating visuals when you’re just hanging out with friends listening to your favorite tunes. Here’s how it works.
Read the rest of the article on Macworld.