What fun activities can I do in my room naked?

get an ant farm.

douse yourself in honey.

release the ants.

or

Again with the honey.

roll in a pile of feathers.

try to remove them.

or

again with the honey

let the dog in.

avoid the dog.

Well, you could clean your room. Do your homework. If your old enough you could even paint it. You can do almost anything nude that you can do clothed. But your mother, would prefer that you do at least the first two.

obviously you want someone to say play with yourself.

Light your pubic region on fire.