This article is a stub. One of us will have to go and actually verify things.
ZIG is a successor to ZZT developed by Aetsch under the Interactive Fantasies imprint in the Euphoria programming language. The final release, 2.1a, was released on August 16th, 2001.
ZIG can be considered one of the most successful unofficial ZZT successors to date, second only to MegaZeux. Not that that's saying much - it still only had about a dozen game worlds released for it.