pretty_dates.rb

# Date formats
Time::DATE_FORMATS.merge!(
  :friendly_date      => lambda {|d| "#{d.month}/#{d.mday}" },                    # 4/25 (no leading zeroes)
  :friendly_time      => lambda {|t|
    date = (t.at_midnight == Time.now.at_midnight) ? '' : "#{t.month}/#{t.mday}@" # 4/25@4PM on other days
    "#{date}#{t.strftime('%I').to_i}#{t.strftime('%p')}"                          # 4PM on same day
  },
  :year               => "%Y",                       # 2008
  :month_year         => "%b %Y",                    # Apr 2008
  :ampm_time          => "%I:%M %p",                 # 04:15 PM
  :two_digit_year     => "%y",                       # 08
  :period             => "%Y-%m",                    # 2010-04
  :basic              => "%b %d %y",                 # Apr 25 08
  :db_date            => "%m-%d-%Y",                 # 04-25-2008
  :slashy_date        => "%m/%d/%Y",                 # 04/25/2008
  :short_slashy_date  => "%m/%d/%y",                 # 04/25/08
  :short_db_date      => "%m-%d-%y",                 # 04-25-08
  :short_day          => "%b %d",                    # Apr 25
  :short_day_no_space => "%b%d",                     # Apr25
  :short_day_time     => "%b %d %I:%M %p",           # Apr 25 04:15 PM
  :short_date         => "%b %d %Y",                 # Apr 25 2008
  :short_datetime     => "%b %d %Y %I:%M %p",        # Apr 25 2008 04:15 PM
  :picker_datetime    => "%b %d %Y %H:%M",           # Apr 25 2008 04:15
  :full_date          => "%B %d %Y",                 # April 25 2008
  :abbr_datetime      => "%m/%d %I:%M %p",           # 04/08 04:15 PM
  :verbose_datetime   => "%B %d, %Y at %I:%M %p",    # April 25, 2008 at 04:15 PM
  :slashy_datetime    => "%m/%d/%Y %I:%M %p",        # 04/25/2008 04:15 PM
  :dashy_datetime     => "%m-%d-%Y %I:%M %p",        # 04-25-2008 04:15 PM
  :day_name_datetime  => "%a, %b %d, %Y at %I:%M %p" # Fri, Apr 25 04:15 PM
)

Date::DATE_FORMATS.merge!(Time::DATE_FORMATS)

:db => "%Y-%m-%d %H:%M:%S",
:number => "%Y%m%d%H%M%S",
:time => "%H:%M",
:short => "%d %b %H:%M",
:long => "%B %d, %Y %H:%M",
:long_ordinal => #<Proc:0x007ffa31fd3bc0@/Users/DDoezema/.rvm/gems/ruby-1.9.2-p290/gems/activesupport-3.2.6/lib/active_support/core_ext/time/conversions.rb:12 (lambda)>,
:rfc822 => #<Proc:0x007ffa31fd3af8@/Users/DDoezema/.rvm/gems/ruby-1.9.2-p290/gems/activesupport-3.2.6/lib/active_support/core_ext/time/conversions.rb:13 (lambda)>

^^ Rails Defaults