gish is a gtk2-perl interactive shell, designed to let you play around with Gtk2 objects, data structures, and code in an interactive setting. It was inspired by wish, the simple windowing shell provided with Tk, in that you can build up live objects.
This initial implementation is dead simple; it reads input lines from you using Term::ReadLine, and evals those lines in the Perl interpreter. A main loop is always running, and the Gtk2 and Data::Dumper modules are imported for you.
Basically, the main advantage of gish over the perl debugger is the integration with the Glib/Gtk2 event loop.