You can find all the sites you want by searching “Referrer Spam” in Google. Basically, spam sites add your link to their site, click it (thus entering their referrer entry into your logs), and delete your link. Not that I support spam, but it is pretty clever. The only way to get rid of it is to modify .htaccess by following the link I had previously posted. Or, you could set your daily stats to show all referrers and just ignore the spam ones.