Hi,
As part of the revamp of the doodle website, I’ve added a page listing
what I consider similar libraries:
http://doodle.rubyforge.org/similar-libraries.html
If you have written a library that is in some way similar to one of
these, I’d be grateful if you let me know so I can add it to the list
(and pinch ideas/code from 
Regards,
Sean