This adds in a set of date related scopes for any timestamp column. Date type columns aren't yet supported.

date_scopes.rb

module DateScopes
  extend ActiveSupport::Concern
  
  module ClassMethods
    def include_date_scopes
      include_date_scopes_for :created_at
    end

    def include_date_scopes_for(column, prepend_name = false)
      return unless self.table_exists?
      if self.columns_hash[column.to_s].type == :datetime
        define_timestamp_scopes_for column, prepend_name
      elsif self.columns_hash[column.to_s].type == :date
        define_date_scopes_for column, prepend_name
      end
    end

    def include_named_date_scopes_for(column)
      include_date_scopes_for column, true
    end

    protected

    def define_timestamp_scopes_for(column_name, prepend_name = false)
      prefix = prepend_name ? "#{column_name}_" : ""

      define_singleton_method :"#{prefix}between" do |start_date_or_time, stop_date_or_time|
        start_time = (start_date_or_time.is_a?(Date) ? start_date_or_time.to_time : start_date_or_time)
        stop_time = (stop_date_or_time.is_a?(Date) ? stop_date_or_time.to_time + 1.day : stop_date_or_time )
        where{(__send__(column_name).gte start_time) & (__send__(column_name).lt stop_time)}
      end

      define_singleton_method :"#{prefix}on_or_before_date" do |date|
        where{ __send__(column_name).lt date.to_date.tomorrow.midnight.gmtime }
      end

      define_singleton_method :"#{prefix}on_or_before" do |time| 
        where{__send__(column_name).lte (time.is_a?(Date) ? time.to_time : time)}
      end

      define_singleton_method :"#{prefix}before" do |time| 
        where{__send__(column_name).lt (time.is_a?(Date) ? time.to_time : time)}
      end

      define_singleton_method :"#{prefix}on_or_after_date" do |time|
        where{__send__(column_name).gte time.to_date.midnight.gmtime }
      end

      define_singleton_method :"#{prefix}on_or_after" do |time|
        where{__send__(column_name).gte (time.is_a?(Date) ? time.to_time + 1.day : time )}
      end

      define_singleton_method :"#{prefix}after" do |time|
        where{__send__(column_name).gt (time.is_a?(Date) ? time.to_time + 1.day : time )}
      end

      define_singleton_method :"#{prefix}on" do |day| 
        between(day.midnight, (day + 1.day).midnight)
      end

      define_singleton_method :"#{prefix}day" do |day| 
        on(day)
      end

      define_singleton_method :"#{prefix}last_24_hours" do
        after(24.hours.ago)
      end

      define_singleton_method :"#{prefix}last_hour" do
        after(1.hour.ago)
      end

      define_singleton_method :"#{prefix}last_week" do
        after(1.week.ago)
      end

      define_singleton_method :"#{prefix}last_30days" do
        after(30.days.ago)
      end

      define_singleton_method :"#{prefix}today" do
        on(Date.today)
      end

      define_singleton_method :"#{prefix}this_week" do
        between((Date.today - Date.today.wday.days).midnight, (Date.today + 1.day).midnight)
      end

      define_singleton_method :"#{prefix}this_month" do
        between((Date.today.at_beginning_of_month).midnight, (Date.today + 1.day).midnight)
      end

      define_singleton_method :"#{prefix}yesterday" do
        on(Date.yesterday)
      end

      define_singleton_method :"#{prefix}most_recent" do
        order("#{column_name} desc")
      end

    end

    def define_date_scopes_for(column_name, prepend_name = false)
      prefix = prepend_name ? "#{column_name}_" : ""

      define_singleton_method :"#{prefix}between" do |start_date, stop_date|
        where{(__send__(column_name).gte start_date) & (__send__(column_name).lte stop_date)}
      end

      define_singleton_method :"#{prefix}on_or_before" do |date| 
        where{ __send__(column_name).lte date }
      end

      define_singleton_method :"#{prefix}before" do |date| 
        where{__send__(column_name).lt date}
      end

      define_singleton_method :"#{prefix}on_or_after" do |date|
        where{__send__(column_name).gte date}
      end

      define_singleton_method :"#{prefix}after" do |date| 
        where{__send__(column_name).gt date}
      end

      define_singleton_method :"#{prefix}on" do |date|
        where{__send__(column_name).eq date}
      end

      define_singleton_method :"#{prefix}day" do |day|
        on(day)
      end

      define_singleton_method :"#{prefix}today" do
        on(Date.today)
      end

      define_singleton_method :"#{prefix}last_week" do
        after(1.week.ago)
      end

      define_singleton_method :"#{prefix}last_30days" do
        after(30.days.ago)
      end

      define_singleton_method :"#{prefix}yesterday" do
        on(Date.yesterday)
      end

      define_singleton_method :"#{prefix}most_recent" do
        order("#{column_name} desc")
      end

    end
  end
end

Also its good to note that this currently relies on the Squeel gem for some of the syntax sugar.