Add your project to the list if you’re using YARD.
This is a free plug zone (not to be confused with a plug free zone). Just make sure to order the list alphabetically (or some other fair manner); this is not a competition of who’s got the best project.
Addressable – A better replacement for URI from Ruby’s standard library
Adhoc – Service discovery and routing for DNS-SD (aka Bonjour), XMPP and AMQP.
Amazon Web Services – Ruby SDK for interacting with AWS infrastructure services (S3, EC2, SimpleDB…)