Are there any QA tools that let me observe part of the state of a Ruby program in a GUI as it runs?

I already know about "irb" but it has a text based user interface. I am looking for something lightweight that I can use to launch a Ruby app, which it will "hook" into and display the state of certain object, class, and module fields.

I want to be able to keep watch on certain things out of the corner of my eye - without affecting the execution of the program in a serious way.

I can live with the application slowing down, as long as it is not to the point where it becomes unusable.