What is the modern way to structure a ruby gem?

Some posts that I have found useful:

• http://chneukirchen.github.com/rps/
• http://tomayko.com/writings/require-rubygems-antipattern
• http://yehudakatz.com/2009/07/24/rubygems-good-practice/
• http://weblog.rubyonrails.org/2009/9/1/gem-packaging-best-practices

Edit (2012-01-10): An excellent all-around guide to gem best practices is RubyGems Guides. I would highly recommend starting here now.

To summarize the key points:

• Use the basic lib/gem.rb and lib/gem/ structure for code.
• Put any executables in bin, any data files in data and tests in test or spec.
• Don’t require or depend upon files outside of the load path. (VERSION files often seem to live in odd places in gems.)
• Do not require 'rubygems'.
• Do not tamper with the $LOAD_PATH.
• If you find yourself writing require File.join(__FILE__, 'foo', 'bar'), you’re doing it wrong.