I never used to think that believing Monday was orange, that Wednesdays were yellow or that the number 2 was a female was particularly unusual, until my girlfriend brought home a copy of a paper with a big feature about 'synesthesia' in it. Or, as Wikipedia, the font of all dubious knowledge, puts it, "a neurological condition in which two or more bodily senses are coupled."
Synesthesia is an odd condition, and manifests itself in lots of ways. For synesthesia 'sufferers', letters or numbers can be associated with colours; days of the week or months can take on personalities; musical notes can have a gender.
Here's some more examples of how I interpret the world:
Friday is dark green.
The number two is a strong-willed female.
The chord of E is also a strong-willed female.
The number seven is a bit of a fey man.
The month of May is white in colour, and female.
The letter Z is female.
It happens with songs too. For example, even though it's sung by a man, I perceive 'Yesterday' by the Beatles as being a female song, whereas their 'Don't Let Me Down' is a male song. I perceive the first song as a grey-ish green; the latter as browny-red.
The more I write these associations down, the more odd this all seems. The links seem completely arbitrary, but you could ask me a question about any letter, number, day or month and I could tell you what colour it is, what sex it is, and what kind of personality it has (and these descriptions wouldn't change, even if you asked me the same question a year later).
The Wikipedia explanations of synesthesia make the mind boggle a bit - particularly at this hour of the night - but regardless of why I have it, I have to say I like having it. It's a nice feeling, and I like being able to assign little personalities and colours to everyday things that quite frankly don't "really" have them.
Besides which, famous synesthisiacs include Beethoven, John Lennon and Jimi Hendrix - so I'm in good company. And the number seven IS a fey man.