Fundraising tournament

[JimHammer]

I'm looking to raise funds for the Leukemia and Lymphoma Society and am thinking about having a poker tournament. I'm just trying to figure out the best format/buy-in/payout and interest level.

My first thought was to have a $50 buy-in freezeout with 50% of the proceeds paids out to the winners and the rest to charity. My sister thinks this is a little high for a buy-in (but she is notoriously cheap). Other options are a smaller buy-in with rebuys, add-ons, or a smaller payout (after all, it is for charity.) Which of these formats would you rather play and which one do you think would raise the most money?

If anyone has any experience in throwing one of these tournaments (fundraisers, not just home tourneys), any information would be appreciated.

Thanks in advance,
Jim