age birthdate verification mod?

[aaronrand]

Hi, I added a adult content type forum area to my site, and would like to enable some way to at least ask users if they are 18+ before they enter, even though they can fake that, at least I do my part in keeping that thread somewhat hidden.
Currently I have a password on it, and an announcement to pm a moderator for password, but thats becoming a pain.
Anyone have or use or can suggest a better way? Just on one forum , not the entire site?