1. HomesickYour home directory is your castle. Don't leave your dotfiles behind.
2. JewelerOpinionated tool for creating and managing Rubygem projects
7. le-gitIt's a GitHub party and you're invited! Ruby wrapper for the GitHub API
8. shoulda generatorRails generators which produce tests using shoulda instead of straight up Test::Unit. Other goodies as well.
11. has ip addressAn extension to ActiveRecord to store IP Addresses in the database as integers
15. has markupManage markup close to home... right in the model! Caching, validation, etc