The scripting is not wrong in the way that does not validate. It is crystal clear css by the book. Validates perfectly.
As I stated earlier, I just got started with ubbthreads so there are no great sites, I can present. However I am working on a blogging frontend over at Zarzals dragon-clan which (at the moment) validates.
http://validator.w3.org/check?uri=http%3...utomatically%29I also worked on the plone cms
http://plone.org which should validate perfectly. (Although this ain't my work, but there is a lot to learn from their css-gurus)
The problem I see with ubbthreads is that it is really hard work to get it to render clean code. The templates are chosen in a way that validation is only possible when they are run and filled with data. Then, seeing the error in the resulting code you have to find the corresponding template, fix it and get on to the next error.
Well, this is stuff I do in my free time, but having seen how things could be makes it kind of frustrating to hack stuff on ubb which clearly has it strengths in other areas.