We did such a fun measuring activity the other day. It was one of those activities that I had planned months ago and didn't get time to do so I kept it in my basket and carried it to school many many days before it finally fit in my plans again. It was also one of those activities that is pretty basic, and you really don't know if it will be a dud or lots of fun. Thankfully, we enjoyed it.
I used the book Actual Size by Steve Jenkins. As I read it, I had our leader for the day up with me to compare her eyeball to the ostriches and her tongue to the ant eaters, etc. We did a lot of comparing as I read. This was the first time we have done any measuring.
One page in the book has a gorilla's hand and a Pygmy Lemur's hand. I traced them both as well as my hand. As a whole class, we measured all three using unifex cubes. We did more comparing and ordering of the size of these.
I had (weeks ago when I thought we'd be doing this activity) traced each child's hand on a half sheet of paper. After demonstrating what to do on their sheet, I had them measure their own hand with the blocks and record the number. They laid them all out and counted them up. We all also recorded the number for the gorilla's hand.