Raspberry PI Rev 1 & 8 Channel Relay module; This script goes through every defined gpio port and powers every relay for 0.5 sec.

relay.py

#!/usr/bin/env python

import RPi.GPIO as GPIO, time as t


#Define GPIO Ports http://bit.ly/14RmXp2
r = [8, 10, 12, 16, 18, 22, 24, 26]

#Setup GPIO
GPIO.setwarnings(False)
GPIO.cleanup()
GPIO.setmode(GPIO.BOARD)

#Go through every port
for i in r:
	GPIO.setup(i, GPIO.OUT)
	GPIO.output(i, False)
	t.sleep(0.5)
	GPIO.output(i, True)