I forked another ruby library today: gd2-ffij, which happens to be a fork of a fork of sorts.
It provides bindings to the gd2 library (think awesome graphics utility) via ffi (foreign function interface).
There is another ffi interface, gd2-ffi, but its limited in the functionality it covers.
This one didn't work with Ruby 1.9.1 right out of the box, but with a little bit of hackage, I was able to get things going. I reported by experience back to dark panda (J) who responded speedily.
Hopefully this will be the standard GD2 library.