Last month I mentioned that Google was accepting ads from a racist, neo-Nazi webstore called NSM88 Records. For a while the ads disappeared, but now they are back.
Since the references to Hitler didn't upset our lefty friends at Google, perhaps this lovely T-shirt will get their attention?
As I wrote then, Google's AdWords policy does not seem to have any real prohibition against these sorts of ads. The closest I could find was this section on "inappropriate phrases."
The best page I could find to complain to Google was this one.