As to what you can put in your side bar, what ever you want. I put in a menu system from my website, and some forum code, but limited myself due to the width of the column to match the site.
All it is is code... a example is here:
http://www.shivasite.com/forums/

Did it last week, I also used a different setup, as I also have a header and footer setup in the table to give it a more polished look, but as it's a pretty new setup, still some work to do on the actual board. No hacks, just mods from this site, plus some extra code