The answer to that question is: Not much for a long time, but some things soon.
I rather abruptly dropped off the face of the planet immediately after the 2.4 release back in October, at least as far as Rubygame was concerned. I didn't even stick around to arrange for someone to take over. I was gone. Poof.
Well, not really. I was still around, still reading my email (but rarely responding), and still following a handful of Ruby blogs. I even did a little bit of Rubygame development: Ruby 1.9.1-preview 1 came out less than a week after Rubygame 2.4 (coincidence?! ... yes :P), and I made some tweaks to Rubygame to try to make it compatible. I never pushed those revisions, and I can't remember whether or not I got it completely working. If I recall correctly, I ran into some issues with having 1.8 and 1.9 installed side by side, and things like Rake and Gems not wanting to cooperate.
Aside from that, though, I pretty much avoided anything having to do with Rubygame. I was tired of it, and I had a big, exciting new hobby project to start swimming in. That project is unrelated to Ruby or games, and I won't be writing about it either here or on my personal blog. It's still ongoing (and probably will be for years), but it's getting mature enough that I don't have to nurture it every day. Plus, I have a project partner to help out and provide support, a luxury I never had with Rubygame. (I did receive patches from time to time, and I did and do appreciate them, but it's not the same thing.)
But as exciting as the other project is, my calling is to interactive media design ("video games"), and Ruby is still my programming language of choice. (Sadly, I don't get to use it on the other project, because we've inherited a code base written it C++). So I find my thoughts these days drifting back to the desire to write games in Ruby.
The sad irony of Rubygame is that I never got around to actually using it much; my energy was entirely on making it. Well, that's going to change. I'm retired from being Rubygame's developer, so I'm going to start being one of its users.
I have decided, though, that I will stay on as Rubygame maintainer. And I really mean strictly maintenance: sweeping away the dust, applying patches, maybe fixing a bug once in a while. I'll probably finish up the Ruby 1.9 compatibility fixes (since 1.9.1 was released recently). But I won't be developing new features. (I'd still like to find a developer with the enthusiasm and energy to push Rubygame into new territory, as I wrote back in October.)
Mostly, I'll be working on two things: a game, and Rebirth (which will probably get a new name). I'll be developing Rebirth as a support library for my game, so they will grow with each other. When my game needs some new feature, it will either be added to Rebirth as a general library, or else it will start in my game and then, after the feature is done, be extracted and put into Rebirth.
In case you've forgotten (or never knew), Rebirth will use OpenGL for graphics, with Rubygame underneath for stuff like event handling and image loading. Eventually, it will have physics support using Chipmunk. I'm toying with the idea of OpenAL audio, but Rubygame's basic audio support will be fine for starters, and I don't want to get occupied developing a Ruby OpenAL library, too.
On rare occasion, some of the work on my game or Rebirth might make its way back into Rubygame. For example, I intend to brush off the improved Clock class I developed as part of the mythical Rubygame 3.0 so many moons ago. Once that's done, I might submit it as a patch to be applied to Rubygame (as crazy as submitting a patch to my own project seems).
For those who are curious about the game I'm planning: it's going to be an ambient music creation toy, inspired by (but not a clone of) Toshio Iwai's Electroplankton. I've had ideas about this floating in my head for many years, and it's time to bring it to life. Let's hope my pessimistic prediction in that old blog post doesn't come true.
Assuming I actually go through with this, I'll be blogging about the game over at my personal blog. Rebirth news might be over there too, since it's not really Rubygame. Although, this blog would get rather lonely. We'll see which way it goes.