Have you ever heard of polyphonic overtone singing? If you haven't, you will probably try to do it the first second you are out of earshot of your colleagues, and you will probably sound very dumb. Polyphonic overtone singing is a way of vocalizing so you are singing two tones at once, seemingly harmonizing with yourself. This lady is really good at it.

Have you tried to do it yet? How stupid did you look/sound?