Setting up a "make your own forum" site? Not sure how to ask this...

[pokerhelper]

Are there any mods or scripts that would allow people visiting my page to setup their own forums on my site?  (multiples, i.e. board a, board b, board c, etc)
So if my friends wanted to make thier own boards, they could just create them on demand, and run them independantly of each other? (adding board d, board e, etc)
Thanks