We had very unique themes for spirit week and I enjoyed participating in all of them with my kids.
Day 1: Dress like your favorite ERA - ours was obviously the 50's
Day 2: Dress like a character from one of your favorite books - Miss Nelson from "Miss Nelson is Missing"
Day 3: Dress like an animal - "Peacock"
Day 4: Dress like "winter" - I just picked winter colors and went with snowflakes, there is one on my sweater and actually a bling sticker snowflake on my cheek by my eye :)