DragonRuby.exe is marked as a Windows application, so double-clicking it won't generate a terminal window. The downside is this means that stdout gets lost even when launched from cmd.exe (dragonruby-publish is marked as a console app, which is why it works there.)  This is a quirk of Windows. I'm making a card on our TODO board to find a better solution to this. DragonRuby already does a few minor things differently when it thinks you're developing a game vs playing a published game, so there's no reason we can't make a separate window in the developing case, too. Stay tuned, we'll come up with something!

Update on this! The build we posted last night has the Dragon Console in it, which keeps all the stdout text, so you don't need a separate terminal window anymore. In fact, using puts() inside your Ruby code will send it to the Dragon Console. Just hit tilde (or backtick...the standard "Quake console" key) to get at it. PageUp will scroll back through the text.

We think this solves the Windows problem pretty well.

Five-minute intro video to show you the Big Idea of the thing: