unless the drinking age is 21 where they live.... (in the us. yes. we're puritanical.)
I second the books. Go to a bookstore and find something that would make you both laugh.
Another option is if she's into any sort of crafts. Knitting, maybe? (but only if you KNOW. and then I highly recomend gift cards. or at the very least receipts.)
finally, does anybody say 'no' to their favorite candy?