Leaders: Andy Lester and Jonathan Rockway
HTML::Tidy is a wrapper around the libtidy validation and cleanup library. It needs some serious attention to increase the access to the inherent capabilities of libtidy. If you know C and XS, this could be the one for you.
libtidy: http://tidy.sourceforge.net/
HTML::Tidy repository: http://code.google.com/p/html-tidy/