People should do more stuff like this, maybe it'll open up our minds to greater possibilities.
As of last week, I've been playing with Pharo Smalltalk, of all things. So far, the combination of a "live" and "manipulable" gui library like Morphic and image-based environment has been great.
I can directly modify things and see the results, which makes it fun again, and I can save my entire project state, open windows and running demos and all, and resume it later when I have time. It means I can do something with half an hour of time, which is often all I have between work and kids. I just pop open the image and I'm back where I was, and I can write a few methods or just play with the objects and save again. Otherwise, it seems like it takes me at least half an hour just to start up emacs or eclipse, load all my project files, start an interpreter, get my brain back together, etc., etc.
It'll never be useful for my day job, but it makes writing silly little visualizations of A* or cellular automata actually fun.