如果赢够多,赌场当场要你的ssn填W-2G表,这个表和工资的W-2一样,是报到IRS的。赌场还有可能会withhold你的收入税。
http://www.irs.gov/newsroom/article/0,,id=108277,00.html
"...the payer is required to issue you a Form W-2G. If you have won more than $5,000, the payer may be required to withhold 25 percent of the proceeds for Federal income tax. "