TZip
TZip makes it a little bit easier to set TimeZones in a rails app, since it can figure out the appropriate identifier from a ZIP code.
Install & Implement
$ gem install tzip
# Gemfile
gem 'tzip'
Usage
# Set the default time zone for a Rails app
# Rails configuration file (config/application.rb or config/environments/development.rb, etc)
config.time_zone = ActiveSupport::TimeZone.find_by_zipcode('90210')