FreeCard is a
open-source replacement of Apple Computer's
HyperCard, which is a
Macintosh-only
rapid-application development tool.
FreeCard will improve on HyperCard by adding more and even easier scripting languages, integrated color support, support for Macintosh, Linux, and Windows, a MUCH faster interpreter, and whatever else we come up with.
It is currently being written. (I am one of the principal developers)