I considered starting this a couple of weeks back. I even contacted Matt Kruse to see if I could base this hack on his free perl calendar script (with proper credit of course).
He replied and told me the only way I could use his script was in the format it is in. Meaning I could not use his code in a distributed package, but could provide users with instructions on how to modify his code to work with UBB.
The modifications to get his code to work would be *VERY* cumbersome so I elected to persue other avenues.
Does anyone know of an existing calendar (preferably under GNU/GPL) that would be a good starting point for this hack?