The only time I know of MTV to play any videos at all is between 4 and 9 in the morning. Exactly when I don't want to watch/listen to videos. Ditto for vh1.
Then again, I gave up on MTV when they quit airing "120 Minutes" - possibly the greatest video program they ever had. Thankfully I had the smarts to tape several of the broadcasts from 1989-1990. Frakking awesome industrial and alternative videos.