It is an odd yet amusing fact that most girls halloween costumes are in the "Sexy" category. I don't really know how that came to be, but it works for me. I guess maybe girls are in the majority more likely to buy the "sexy whatever" costume than anything else. Who knows, I'm not a psychologist or a sociologist. Maybe girls just want attention and like having Halloween as an excuse.
A year or two ago CollegeHumor.com came out with this video. I was reminded of it earlier in the day thanks to bannination.com. Here it is.