Is one halakhically allowed to become a drug addict? How about a gambling addict? Or a smoking addict?
R. Mordechai Willig spoke recently about Gambling in Halakhah and answered all of the above questions in the negative. He quoted a 1972 article by R. Ahron Soloveichik in Tradition, in which the latter based the prohibition on the Sefer Ha-Hinukh's understanding of the verse "that you not stray after your own heart" (Numbers 15:39). This, R. Ahron Soloveichik argues based on the Hinukh, precludes becoming addicted to anything. R. Willig explicitly applies it to gambling, smoking, drugs and... overeating.
He points out the "mitzvah" aspect of such activities -- getting hooked on alcohol at simhos, starting to smoke on Purim, and gambling on "Nittel" and Hanukah. He quotes the Arukh Ha-Shulhan's harsh words against gambling with dreidels and cards (R. Willig: "I give you a heter to learn on Nittel Nacht").
What about Chinese Auctions and charity raffles? I'm guessing that these are also addictive gambling and that R. Willig's strong words apply to them as well.
UPDATE: To clarify, R. Willig is very concerned about people whose addictions being with what many consider to be mundane instances. One Purim cigarette a year isn't going to get you hooked. But, study after study tells us, every addict begins with that one cigarette. Every gambler starts of with some innocuous form of gambling. It behooves our community to not start people off on paths of addiction.
I should add two things. First: R. Mordechai Willig does not discuss Chinese Auctions. That is my extension of his comments. Second: R. Asher Meir disagrees.
So, if your gambling event is meant to be an entertaining evening for people who are happy to support your organization, by all means go ahead. But if you want to create a business which will cater to gambling aficionados, then you must be extra careful not to take advantage of people nor to condone gambling as a way of life...link
You're on safe ground if everyone feels they're in a "win-win" situation: either they make a little money, or they give much-needed help to a worthy cause.