You might also try some of the Marriott / RC discount codes publicly posted here on FT. You may or may not be entitled to use some of them, so caveat emptor.

I have found particular success in using codes for companies that have large offices or headquarters nearby, but almost never have success at resort properties. Never been asked for a business card or corporate ID, FWIW.

Please, save the flaming. I get enough of that on the AA board. I know I'm a bad person and I'm setting a bad example.