In this writer's opinion, nothing defined the gradual change in MTV in the 90's more than the development of its animation department, starting with Beavis & Butt-Head.
Texas animator Mike Judge introduced his dim duo in the short, "Frog Baseball", which premiered on Liquid Television. MTV viewers loved it, and so the teen twits were given their own series. It initially launched in March 1993, but because not enough episodes were produced to justify a daily berth, the series was pulled after a couple of weeks, allowing Judge time to develop enough of a backlog to keep the show going. Beavis returned a few months later, and MTV was never the same again.
Beavis & Butt-Head lasted 4 1/2 years overall, ending in December 1997, during which time Judge expanded, sending the boys into a feature film (1996's "Beavis & Butt-Head Do America"), and finding the time to have Beavis & Butt-Head record a novelty remake of Sonny & Cher's "I Got You Babe" with Cher herself. Their Christmas special, parodying "A Christmas Carol" & "It's A Wonderful Life", remains a favorite.
Following, however, is "Citizen Butt-Head", in which the boys meet President Clinton (voiced by an impersonator). Then-MTV News anchor Tabitha Soren guest-stars.
Edit, 12/10/16: Unfortunately, the complete episode is no longer available. We'll settle for this short little excerpt:
The series was revived in 2011, but it doesn't appear as though it took so well, marking the characters' 20th anniversary as it did. Of course, MTV isn't exactly a good landing spot for toons these days.