Babies of all species are usually either hard at play or fast asleep. There is little time to do much else. If they go too long without doing one of those two things, all hell might break loose.
In this video, two little kittens were taking turns playing with a toy. One of the kittens was too tired to continue. If fact, the kitten was too tired to even stand. What an adorable little creature. Hopefully she gets a good nap and goes back to doing all the precious things that kittens do.