Just a little insight here as I saw earlier someone brought this up.
In your instructions you create the calendar to display on the top of all forums through the add table function. I followed your instructions to a tee and I did not like what I saw. Great work on the hack but I think most people would like to see threads not a calendar staring them in their face when they enter a forum. So here is what I did and I hope I did it correct. I made another forum called calendar and made sure the BO_Calender field had Y in it for that particular forum. I then edited all other forums to blank ( no Y ) so that there is nothing on that table and optimized my tables. I end up with forums all normal and a calendar forum which displays the calendar.
My only question is the table field Bo_Calendar for all the forums that are set to nothing is this fine?
Everything is working right.