Michelangelo (originally Michaelangelo), nickname Mike or Mikey, is a fictional character and one of the four main characters of the Teenage Mutant Ninja Turtles comics and all related media.
He is usually depicted wearing an orange eye mask. His signature weapons are dual nunchaku, though he has also been portrayed using other weapons, such as a grappling hook, manriki-gusari, tonfa, and a three-section staff (in some action figures).
More fun-loving than his brothers and the youngest of the group, Michelangelo was given a much bigger role in the 1987 cartoon series, directed at a younger audience, than in the more serious original comic books which were aimed at an older audience. He often coins most of their catchphrases, such as "Cowabunga!". Like all of the brothers, he is named after a Renaissance artist; in this case, he is named after Michelangelo Buonarroti. The spelling of the character's name varies from source to source, and he has been alternately shown as both Michelangelo and Michaelangelo.
Source: Wikipedia, "Michelangelo (Teenage Mutant Ninja Turtles)", available under the CC-BY-SA License.