I have made the following addition to my b2comments.*.php file.
/* Check for specific words from a spam array */
$author_lower_string = strtolower($comment_author);
$words_array = array("sex","viagra","texas","holdem","poker","online");
/* End word check */
And I want to share it with others, so here you are.. Hope you can use it.
Later on I think I will submit a patch for wordpress, possible with a menu-point in the administration module, where you can submit words without entering the code. But more to come I think.