Ralph Wiggum is possibly the most annoying, but certainly the most quotable character in The Simpsons television show, voiced by Nancy Cartwright.

He is the 8 year old offspring of Chief of Police Clancy Wiggum. Having Chief Wiggum as a parent has led to a very strict upbringing for Ralph, an example being him having tethered swimming as his gym activity.

The strict upbringing may account for the fact that he sees leprechauns who occassionally tell him to burn things and that he wants to be a caterpillar when he grows up. Despite this, he has been allowed to have a pet cat, who he calls "Mittens", who hasn't come to harm. Yet.

Often referred to as the class clown, Ralph is a classmate of Lisa Simpson in Springfield Elementary where they are in Mrs Hoover's 2nd grade class. Although occasionally he befriends Bart Simpson or Lisa Simpson, Ralph does not have many friends. In one episode he did however manage to go on a date with Lisa Simpson, who he has a crush on, to see the Krusty show, where Lisa announced on live TV that she didn't like Ralph.

Ralph's greatest moment was when he was awarded 1st prize in the school's "Diorama-Rama" contest with his entry of a box of prepackaged Star Wars figures. Another feat for which he was proud of was his appearance in "Hooray for Presidents day" where he made a successful portrayal of George Washington. So successful that he permanently glued a powdered wig to his head which later had to be removed due to his scalp being infected by ringworm. Having said this, it did take him three years to get beyond training wheels when he was learning how to ride a bicycle.

Sources:
http://www.snpp.com/guides/ralph.file.html
http://www.nohomers.net/mmmpaste/bio/index.html
http://www.geocities.com/TelevisionCity/Set/1676/ralph.html