Smelling Sounds, Hearing Colors

Humans can hear colors and smell sounds. Its called synaesthesia and affects ~1 in 1,000 people - most not knowing they have the condition.

"There are people for whom time units evoke colors ... It is also common for a synaesthete to see colors when listening to words, sounds in general or music notes (people who can see music, for instance). There are also cases, although fewer, where people can see colors in flavors, others perceive flavors or experience touch sensations when listening to different sounds, some link flavors to touch sensations, etc."