You bet! Sorry it took me so long to get back to you.
Here's how it works:
Panda3D was developed at Disney Imagineering to work some of their theme park attractions. "Pirates of the Carribbean," for instance. They built a platform which looks like the deck of a ship, with cannons around the side. The platform is surrounded by huge projection screens, so it's like a 3D cave. On the screens, pirate ships. The people on the "ride" have to work the cannons to take out the pirate ships. I've heard it's a pretty good attraction.
Anyhow, back then, the engine was fairly primitive - although it did have unusually flexible I/O design, to work the cannons and the multiple monitors.
They used the engine in a couple more attractions, and each time, they ended up adding features and making it a better engine. Then, they decided to use it in "Toontown online."
Then, in 2002, Disney decided to make it free software. I'm not sure how that came to pass. I know the main developer for Panda3D, David Rose, and he's the kind of guy who has a very relaxed view of intellectual property rights. For example, the kids on the Toontown forums are always asking "hey, how can I rip the toontown art assets," and David Rose gives them technical help. That's the kind of guy he is. Speaking from my own experiences working on "A Tale in the Desert," I understand where he's coming from. Nobody's going to steal your art and make a game that competes with yours. It just takes too long and too much effort. So there's simply no reason to be all bitchy about IP. I think David Rose understands that.
So anyhow, they made it free software, and one of their employees (Jesse Schell) moved to Carnegie Mellon's Entertainment Technology Center - which I can tell you is a very cool place. We've got about a hundred kids at a time, all learning how to make VR worlds and that kind of stuff. So we needed a 3D engine, and Jesse told us about Panda, and we sort of adopted it as the ETC's official engine. So now we're working on it too, along with Disney.
By this time, the engine had gotten pretty dang robust. After using it in three or four real projects they'd worked out most of the bugs, and then the students start banging on it, and let me tell you, they really know how to find bugs. So with all these people putting it through its paces, it's gotten very solid. It's not the fastest engine around, but what I like about it is how reliable it is. Any engine that you can give to a team of college student and they can't break it is a pretty useful engine.
As for me, I'm the guy at ETC who coordinates the development of Panda3D on our end. (I don't really have much to do with Disney's development team, except that I'm always chatting with David Rose, asking him for help on stuff.) My main job is to fix minor bugs, make minor tweaks, and manage the distribution.