Firstly and perhaps most noticeably (for me at any rate) whenever i hear a sound it has a sort of shape, depth, and colour in my mind's eye. For instance, most people's voices are yellow and sort of rubbery; a piano key looks like a blue pearl, etc.
Letters and numbers have a sort of "assigned" colour, because of this i'm really good with names and dates; days of the week and the months of the year also have a shape and colour (i only learnt recently that i'm not the only person who has this).
i've also noticed recently that types of pain seem to have a colour as well (i have a headache right now and it's this sort of pulsating orange, oh dear.)