Oh my, my students LOVED this lesson. Thanks to Art Room Video's (http://artroomvideos.blogspot.com/) for posting this and giving me this idea.
It centers around the awesome They Might Be Giants "Roy G. Biv" video. I showed the students the video (they will then demand you show it every time they come to class from that point on), and we talk about the color spectrum. I pass out papers for them to write the name of the colors on back and on the front they draw their rainbow. I was very pleased to see Roy himself make an appearance on many of the drawings. It's a very quick 1 day lesson, unless you play the video more than once, then it can take up to 3 days.
This lesson works well with 1st - 3rd grades. Enjoy the fruits of their labor!
Oh, and here's the video...