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.

Using a recent version of passenger and rvm head along with project-specific gemsets? Thanks to the new rvm ruby api, it's now relatively trivial to have rvm automatically switch gemsets / set BUNDLE_PATH for your application.

I very recently released Barista - an alternative to bistro_car for handling coffeescripts in Rails applications. You can read why I wrote it and what it offers - namely, simple framework support like compass does for Sass.

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.

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.