How can I temporarily change my eye color?

I am going to a costume party for which it is necessary for me to have an unusual color (to go with my costume). I don't wear contacts though, and I don't want the change to be permanent. Is there any way to do this?How can I temporarily change my eye color?
Even though you don't wear contacts, the easiest way to change your eye color is to get that color of contacts. You can buy them so that they don't change your vision, just the color of your eyes. I used to have ones that made my eyes look like cat eyes.How can I temporarily change my eye color?
Contacts are the only way to change your eye color temporarily.