if you have a fanpage, and want people to comment on your fanpage so their friends can see it and possibly join, then try posting this comment as a game:
"Game Time: Last person to comment below will win Page Admin status! All you have to do is be the last person to comment on here! 3, 2, 1.... GO!!"
and then you post the first comment saying:
"haha, im first "
It works an absolute treat, you'll get bombarded with comments and it'll add loads of people to your fanpage!