IE6 hate seems to be increasing in the web circles I run in. Pushup uses javascript & CSS to suggest that people upgrade old browser. For a more aggressive approach, there's KillIE6, which tries to trick people into upgrading to IE7. (via http://gadgetopia.com/post/6551)
seed-fu - Another option for loading seed data into a Rails application.
EditorKicker - Tool to automatically pop open your editor at the right source code line when Ruby raises an exception. There's a Rails plugin for it too. (via RubyFlow)