Fortune cookies by the bulk?
There's a fortune cookie factory on the east side of a north-south alley in Chinatown. You can buy them there by the bag. I don't remember the name, but I believe it's on either Waverly Place or Ross Alley. When I was last there, they even had "adult" fortunes -- which weren't as risque as they made them sound, but might be fun for a party.
re: Marc P
I walk by a place on my way to work called the Mee Mee Bakery. It's right next to Walgreens at 1328 Stockton(@Broadway). They come in traditional, chocolate and strawberry flavors, various colors and sizes. They are $3.60/# and you get about 50 in a pound. You can have custom fortunes inserted for $20-/per 100, and it takes 3 to 4 days. The bakery has been around since 1950 and they are really nice.