As always, it should be noted that it seems likely that people who got high scores would be more likely to post theirs (few people like to show off as below-average!), which is one reason taking an average of the scores posted on this page isn't indicative of an HN average score.
(Me, I got 26. They don't call me Mr. Average for nothin'.)
EDIT: If I'd gotten 25, do you think I'd have included that last line?