Links to individual illusions (the article above has explanations):
Barber shop: 3D realistic stereo experience.
Phantom words: "As you listen to it, you'll start to pick out specific phrases. However, none of the phrases are really there. Your brain is constructing them, in a bid to make sense of a meaningless noise. Indeed, you may find that the phrases you hear are related to what's on your mind – for example, people who are dieting often hear phrases associated with food." To me it just sounded like two women saying 'Nowhere'; what that says about my preoccupations I wouldn't like to say (*)
Musical scales: ' The brain reassigns some of the notes to a different ear in order to make a coherent melody... Right-handed people tend to hear the high melody in the right ear, and the low one in the left, while left-handers show a more diverse response.' (NB this is what I experienced, and I am right handed)
(*) ETA according to this metafilter discussion a lot of people heard 'nowhere', but also words such as 'background,' 'Melvin,' and 'Belgrade'.
Here's another one - watch with eyes open and closed - sounds different.