Preferably at night, stare at an object, such as a tree or sign. Keep both eyes fixed on that object and lift your cell phone to your right eye. Continue to keep your eyes on the object and your phone lit. After 30 to 45 seconds, remove the phone and look around. One of your eyes will only see red and one will only see blue.
It's insane when you're high. Everything seems to be in 3D. Have your friends fake punch you in the face or something.