How Can You Tell When a 6 Year Old Is Really Tired?

When you go through the hassle of bringing the trundle bed mattress into the playroom so you can jump on it and you end up crashing out. If you notice, he also moved the beanbag up there, too.

When I told him to move the mattress back to his room he informed me that "It took like 2 hours for me to get it in here". Guess all that effort was just too much.