I used Manic Panic back in college cherry red and purple. If your hair is dark you will need to bleach it in order for the bright colors to show up. I've also used kool-aid, but again if you want the color to show you will need to bleach your hair first. IF your going to bleach your hair I would recommend getting it professionally done. I didn't and I did some serious damage!
3c/4a 3 Years Relaxer Free!

http://public.fotki.com/curlynyrican/