class Time

def seconds_since_midnight

Time.new(2012, 8, 29, 23, 59, 59).seconds_since_midnight # => 86399.0
Time.new(2012, 8, 29, 12, 34, 56).seconds_since_midnight # => 45296.0
Time.new(2012, 8, 29, 0, 0, 0).seconds_since_midnight # => 0.0

Returns the number of seconds since 00:00:00. 
def seconds_since_midnight
  to_i - change(hour: 0).to_i + (usec / 1.0e+6)
end