We've just released the first public version of RocketPants, a set of tools built on top of ActionController to make building reasonably designed API-specific portions of your applications a little bit easier.
Sutto — 5 posts
ReversibleData for Testing github.com
ReversibleData is a fairly new gem built to solve one of the problems associated with testing AR-backed models - Managing a database (and associated tables) and models. It handles creating / dropping tables and creating / removing models (e.g. so a User model may only exist in the scope of a test). It's like migrations but a lot simpler / scoped to make testing easier.
Mapstraction + GeoKit with Rails blog.ninjahideout.com
Mapping stuff may be old but it's still a handy topic - Mapstraction and Geokit make it really easy to add geographically-specific information to your application without issue. In my recent post I covered both briefly and how / why they're handy.