A person I know from another LGBT forum I post at has a blog and he made a parody of the famous billboards popping up all over the US which offers to "cure" you of your homosexuality. Seems this pissed off Exodus and they have now contacted the blogger and asked him to cease and desist LOL: http://justinsomnia.org/2006/03/my-first-cease-and-desist-letter/ He's looking for legal advice as his stance is one of "Fair Use" for parody.
Of course, the response by Exodus only serves to give the parody billboard just that much more attention.