Sweet 16 Birthday Ideas?

I'm turning 16 in July. I have a group of friends I can invite and a few close close friends. I'm not one to have a bunch of attention and I also am not this huge social light extravagant person. I originally thought a fancy dinner and some games while out to dinner, but it was kind of expensive.

I don't know if I want casual party, but I don't want super crazy so I'm open to a bunch of ideas whatever can be thought of! I also thought maybe a spa day? But I don't know. I'm looking for some creative ideas! Any idea will help. I am undecided if it will be girls only or if it'll be girls and guys I don't have many guy friends, it would probably be my family that was the guys. So either idea will be great! Thanks everyone.