Ask HN: How to find entry-level Ruby projects on GitHub?

Until recently I've used PHP for building my web applications. I'm learning Ruby, and the best way I could think of is to contribute to other projects. I set up a GitHub account and followed the excellent tutorials. My problem is that I can't seem to find any entry-level issues that I can contribute anything meaningful to.

There are tons of tutorials on how to create a simple blog in Ruby, but I'd much rather give something back to the community while learning. Or should I just buy a book, learn more about Ruby and return when my skills are up to par?