The Language Machine is a toolkit for language and grammar: a library, main program, and self-hosted rule compilers with one frontend. The system is easy to use. It directly implements unrestricted rule-based grammars with actions and external interfaces.
EntAgent is a tool for map-makers who map for source-engine based games (HL2, etc...).
EntAgent allows you to edit entity info(keys, outputs) with a text editor, so that you don't have to use the cumbersome hammer entity dialog.