You guys are missing the point. It's Halloween. New Year's is the only of those holidays that make people want to make out, but Halloween is a popular time for house parties. So, you combine women in their best ho costume and the built in excuse to act like their costume would suggest. And you have the house party atmosphere, where chicks are more apt to hook up with you because you aren't some stranger in a bar. Even though you may be a stranger, being at the house party suggests that you at least know someone at the house party who knows someone who knows someone at the house party, who knows the girl you are hollerin' at. Makes women more comfortable. To top it off, you have attention drawn to yourself because it is your birthday. I do agree however, that most Halloween parties are the weekend before. So, 10/24- 10/30 may be the best birthday. Not everyone goes out for the 4th (more of a family holiday IMO). Not everyone goes out for St. Pattys. Cinco de Mayo...are you serious? NYE is lame. Most sane people stay home away from the crazies. Plus you have women w/ NY resolutions of not being the ho they were on Halloween starting that night. Any non-holiday, you risk not having very many people out to get the attention needed to make your 21st b-day great.