IMHO, "Threads are like goto" is a little harsh ... But the more I think about it a well implemented actors model http://en.wikipedia.org/wiki/Actor_model seems way more attractive than threads. Go Rubinius :)
Or dramatis (http://dramatis.mischance.net). Making it dead simple to tie together a graphical front end process with a general backend process was one of the motivating use cases. It's not quite ready for that yet, though; it has all the intraproccess stuff, but not the interprocess stuff. It does have a demo with FOX integration, idiosyncratic as it may be. I've been wanting to integrate Shoes since I much prefer it to "old style" graphics toolkits, but it's still a few items down on the priority list.
