A quick gist on how to extend date formats in rails 3.
# Rails 2
# config/initializers/date_formats.rb
ActiveSupport::CoreExtensions::Time::Conversions::DATE_FORMATS.merge!(
:date => '%m/%d/%Y',
:date_time12 => "%m/%d/%Y %I:%M%p",
:date_time24 => "%m/%d/%Y %H:%M"
)
# Rails 3
# config/initializers/date_formats.rb
Time::DATE_FORMATS.merge!(
:date => '%m/%d/%Y',
:date_time12 => "%m/%d/%Y %I:%M%p",
:date_time24 => "%m/%d/%Y %H:%M"
)