Fred and George Weasley were identical and mischievous twin wizards born on 1 April, 1978 to Arthur Weasley and Molly Weasley (née Prewett). Brilliant pranksters, they co-founded and ran the joke shop Weasleys' Wizard Wheezes and were members of both Dumbledore's Army and the Order of the Phoenix. See their individual articles for more information:
The actors who portrayed Fred and George are James Phelps and Oliver Phelps respectively. Oliver is actually the older twin, but Fred is older than George. The difference between the Phelps twins is that Oliver has a mole on the right side of his neck, while James does not.