Sanguine is a project mainly written in Objective-C, it's free.
Quartz Composer patch executes MacRuby
quartz composer plug-in which executes MacRuby with an arbitrary number of input and output parameters. the plug-in needs to run in a garbage collected host, as MacRuby runs in the ObjC Runtime and requires GC to unify Ruby and ObjC memory management. the quartz composer editor does not currently support GC, a separate host should be used.
requires MacRuby framework at build and run time. MacRuby