[cd34]

RewriteEngine on
RewriteCond %{HTTP_REFERER} ^http://(.*\.)?fatfred.com [NC,OR]
RewriteCond %{HTTP_REFERER} ^http://(.*\.)?fode-me [NC,OR]
RewriteCond %{HTTP_REFERER} ^http://(.*\.)?5isex.com [NC]
RewriteRule .* http://www.google.com [R,L]

you would have blocked http://fatfred.com from linking to you, but not http://www.fatfred.com.

you can also do something like:

RewriteEngine on
RewriteCond %{HTTP_REFERER} fatfred.com [NC,OR]
RewriteCond %{HTTP_REFERER} fode-me [NC,OR]
RewriteCond %{HTTP_REFERER} 5isex.com [NC]
RewriteRule .* http://www.google.com [R,L]

which will block www.123fode-me234.com