YTPMVs

 Several additional links follow at the end. 

Sentence-Mixed YouTube Poop Music Videos, also called "YTP songs" or "YTP karaoke", are videos in which the words of a character are sentence-mixed to match the background music, usually being an instrumental (karaoke) track of an existing song. Unlike using parts of ready sentences uttered by those characters, however, emphasis is put on creating completely new words or meanings, precisely matching the lyrics of a song - a process of focused word splicing. Poopers that have created more than one of those include: TheChewanater, Moto200, HarterStuhligan.

[SOURCE: http://youchewpoop.com/wiki/index.php/Sentence-Mixed_YTPMV]

YouTube Poop is a Neo-Dada art form consisting of video remixes that are edited from a large array of video clips in order to confuse, stun or entertain the viewer. The source material can be mashed all together into a nonsensical Cross Over story, or just repeat footage of the characters gesticulating oddly or apparently saying something dirty over and over and over again. There are also well-known phrases such as "PINGAS"◊ or "Do a Barrel Roll!"◊.
YouTube Poop started with SuperYoshi testing out Windows Movie Maker, a new piece of software he found in his newly installed Windows XP, using the episode "Recycled Koopa" from The Super Mario Bros. 3 cartoon. The result was a video containing a few clips from the episode repeated and used in a random manner. Later he put this video as The Adventures of Super Mario Bros. 3 Remixed on December 22, 2004, up on his SheezyArt page. The video was well received and SuperYoshi together with his friend RetroJape made similiar remixes using The Megaman Cartoon and later Adventures of Sonic the Hedgehog. A few more of SuperYoshi's friends joined and started putting their videos on You Tube in order to confuse and anger people who were otherwise looking for regular Super Mario or Sonic The Hedgehog videos. The first three Poops have been brought to YouTube later as I'D SAY HE'S HOT ON OUR TAIL, Dr. Light's Guidance System Show and Robotnik's Sodomy Fest of 2005, respectively.

[SOURCE: excerpt from long feature at http://tvtropes.org/pmwiki/pmwiki.php/Main/YouTubePoop]

SOURCE for the following (which is just an excerpt from a long feature + user comments), including this definition of 'YTPMVs': http://knowyourmeme.com/memes/ytpmvs

YTPMV

A YTPMV, or Youtube Poop Music Video, put simply is a musical Youtube poop and a western equivalent to a [MAD] video. Like a Youtube Poop, they feature various clips from tv shows, movies, commercials, and other video sources, but the clips are sequenced to fit to a beat. Often, they are set to the tune of a song from a video game soundtrack or keygen music. Other times, original compositions are created. Much like “Trolling” YTPMV is often considered “a art”.
The Urban Dictionary defines YTPMV as:
a music video featuring various clips from tv shows, movies, commercials, etc. repeated or sped up/slowed down to fit to a beat, usually techno.

Concept Origin

The term “YTPMV” first originated on Youtube in 2008 and stems from the video YTPMV: Dr. Octagonapus uploaded by Youtube user MrRoboto113:“http://www.youtube.com/user/MrRoboto113”; on January 29 of 2008.

WANT TO FIND OUT MORE? SEE...

http://ultimatespamgrover.blogspot.com/2010/12/favorite-youtube-poops-of-2010-also.html
http://youchewpoop.com/wiki/index.php/Sentence-Mixed_YTPMV
http://www.youtube.com/watch?v=bWje-bdL8-4
http://tvtropes.org/pmwiki/pmwiki.php/Main/YouTubePoop

And here's the YouTube how-to (linked above) to finish: