gistfile1.txt

def loggable(logger)
  @@logger = logger
  def method_missing(meth, *args)
    if meth.to_s =~ /^log_/
      @@logger.info "#{Time.now.to_s} - #{meth.to_s.split('_')[1..-1].join(' ')}" 
    else
      super
    end
  end
end

class Something
  loggable(Logger.new('log/something.log'))

  def do_something
    log_doing_something
    # do the actual something
  end
end

s = Something.new
s.do_something

# in log/something.log...
# Thu Jun 25 12:12:40 -0400 2009 - doing something