Hobbies for 15 years old????

Ah, I understand what you mean. I've been in this same situation as well and I'm 15 too :] Many 15 year old who love to have time alone (like myself) can do many things. You can draw, maybe take some lessons online to be an expertise in that area. You can also find some good math or puzzle games (Funmathgames.com) you can play regular games here (addictinggames.com). You can be creative and find something old in your closet, any type of clothing of go to youtube and find ways you can accesorize by adding things onto the clothing. Knitting seems like a very calm thing to do. If you love singing, you can also take FREE lessons online! Youtube has it all! you can do some beginner photography and take beautiful pictures of nature.