Here's a fun way to learn all about blue!
I'm not sure if I'm in the minority or majority with this, but I really don't mind if my kids color on their bodies. We have a few rules...they must ask first; they must use washable markers; they must not eat the markers; and they must not color their faces (E(1) is still working on the last 2!).
The girls had SO much fun coloring themselves. It kept them quiet and busy for quite a while. E was especially engrossed in trying to color her toenails. Elliott came home from work while they were doing this, and I quickly asked him before he saw them "You don't mind if the girls color themselves do you?" He didn't, and he even joined in on the fun by drawing pictures on their hands and backs. They thought this was fantastic.
My mom was appalled, but I'm sure she enjoyed watching all of the craziness :) It took 2 nights of baths/showers to get all of the blue off of their bodies, so this is definitely not an activity that we'll do on the night before O(4)'s recital!
Btw, a reader asked me to include the girls ages by their initials since it can get confusing to remember which initial goes with which girl. So, we are now O(4) and E(1).