Contacts ;) Not everything has to be a spell, in fact, I would recommend exhausting all mundane options before attempting a spell. Murphy's law has a much lower chance of pwning you in mundane things.
As much as I agree with both of you in the mundane option, I have to disagree with being able to get a wider range of colors. I can think of many different colors that probably don't work with contacts. I don't know though.