I, of course, have no idea but I'm starting to really look forward to seeing your game! :)
I guess the idea would be having a pop-up like this:
I would look to do it inside a JQuery dialogue:
Now I'm imagining a ball bouncing around the output area, obliterating text as it goes, but you can maybe placate it by bouncing it off the cursor at the bottom :p
Now I'm imagining the input bar transformed into a little spaceship that shoots the text in the output area!