Why on Earth would the transaction logs balloon out of control to such a drastic size without any posters?

Dear rlasker3,

I believe It's happening because the SQL SERVER does not restrict growth you can tweak this and limit the growth in
the SQL SERVER Management Studio Please se the link below: 

http://support.microsoft.com/kb/873235/

You can also shrink the transaction log using the Maintenenance / SQL Maintenenance links in the InstantForum admin area, this may take a little while so you would need to extend the query time out within the web.config (InstantASP_CommandTimeout) to allow for this.