Jazz or tap
Jazz is very easy for beginners. I did it when I was younger and miss it. I'd join again, but I do ballet, hip hop and tap and I also have homework and horse back riding.
Tap is alot of fun too! I do tap, and I've done it since I was 6. I love it.
Hip hop is fun but I think you should try jazz or hip hop first.
Ballet is great too-it's a good excercise.
Ballroom is another option. I did that when I was younger but quit because I didn't really like the slowness of it.