Chances are that it's a bot visiting, not a human. It's an old SEO link spamming trick. Their shows up in your logs as a referer. Some sites have their logs (or log analysis) accessible through a link, so they become spidered. There are also some programs that show recent referrers to the page on the page itself. Either way, the spammers get a link.
Another possibility is that the person that put the referrer there wanted you to visit the website for some reason.
I don't believe you can really do anything about it -- perhaps ban the IP that visited with the bogus referrer.
Wasnt know that trick what a waste of time.This is like seasonal it ssuddenly starts for gamble,viagra sites at my referrer logs and after 2 monts they gone for couple months but that makes me sick anyway and sure it wont work banning their IPs since they always come with new domains.