RELAX

A simpler bombshell At XTech 2000 in March, Murata Makoto (a former member of the XML Schemas Working Group) presented his latest work: a much lighter-weight 'document grammar' that could conceivably replace XML Schemas Structures.
ISO vs. W3C XML work at the W3C began in part as a reaction against the slow development of SGML at ISO. If RELAX gets through the JIS and into the ISO fast-track, the W3C might see a late contender completed before XML Schemas gets to the Recommendation phase.
Other bombshells Document Structure Description (DSD) uses some similar ideas to those in RELAX, but uses a more familiar top-down approach rather than RELAX's bottom-up approach. This work is also producing a simpler but capable set of tools.