Every release is called by some word and a number. I don't know if there's a pattern to it. But for that particular release, it happened to be called Raisins, as far as I could tell.
_why (the author) is using it as a platform to write hacketyhack, a set of libraries and tutorials to help teach kids how to program, but letting them build blogs, downloaders, etc. in a couple lines.
Ubuntu calls its releases "Hardy Heron" and "Intrepid Ibex"
OGRE3D calls its releases "Eihort" and "Shoggoth"
I assume they're following the model of attaching a name to each official release.
To reply to the rest of your comment, I think it would be more exciting for beginners to learn how to program games. There is a much higher effort:reward ratio, though. You can't write Pong in 2 lines of code quite yet.
_why (the author) is using it as a platform to write hacketyhack, a set of libraries and tutorials to help teach kids how to program, but letting them build blogs, downloaders, etc. in a couple lines.