brithday party ideas for a 13 year old?!

Im thinking about throwing a birthday party for my friend but i have no clue what to do. It cant be too expensive and nothing super huge but i need fun ideas for maybe 15-25 girls and maybe some boys. I need a theme and some good ideas for decorations, and some fun stuff todo other than the regular truth or dare and stupid bored games. The games we play need to be kinda big because of how many girls will be there. I already know we are going to have some dancing and music going on so i also need a bunch of good rock and dancing songs.