My then DS5 had his passport stamped, and built a mask, throughout WS. My DS16 got into it, professing only "wanting to help his little brother". It was great fun for both of them, to the point we had to tear them away from some of the kidcot stations.
A side note: by sheer coincidence - a song he learned in Pre-K - my DS5 knew "hello" in Japanese. The CM was impressed when he put his hands together, bowed out of respect, and told her hello. She spent a couple of extra moments with him, making it a little more special for him. Somewhere around here there's a thread with that describes how to say hello in various languages.
Good luck, and have fun!