Hi Hutch,
I'm usually concerned to give user advise to run scripts on their database, but you could do something like this:
update users
set updatePassword = 1
where userid > 10
I add userid greater than 10, but you can adjust that so you don't force host nor admin users to have their password reset.
For security (and disclaimer) I would recommend a full site and db backup to prevent potential misuse. :)
cheers,
Aderson