A long time ago, on a cable channel not so far, far, away from the ones we have now, a certain "musical" channel played music videos.

In fact, this unnamed channel that primarily focused on "music" played the videos that showcased them from sun-up to sundown and all the other hours in between.

Some of them featured more than just the musicians that brought the music to life. They also featured up-and-coming talent, some of whom got their big start on this mysterious "musical" channel.

These days, the music has, well, died and the format that made that unnamed channel such a revered pop culture icon has been lost to the sands of time and trashy reality shows.

There's no other show on TV more perfect for musicians to guest star on than 'Glee' -- but it isn't the only show our favorite artists are angling to snag a cameo on. Some make sense, like Britney on 'Glee,' but others are just flat out bonkers -- like Boy George on 'The A-Team' or, more recently, rapper Kid Cudi appearing on The CW's yes-it's-still-on 'One Tree Hill.'

There have been a lot of head-scratchers over the years. It's crazy and oddly amusing at the same time, so check out our list of the most bizarre musician TV cameos after the jump.

There are two kind of celebrity cameos on HBO's 'Entourage,' which returns Sun., June 27 at 10:30 pm ET. The first is a quick walk-on by a star or athlete, usually done to illustrate the orbit the characters of 'Entourage' travel in. For instance, Eric's encounter with NBA star Steve Nash in uber-manager Murray Berenson's waiting room last season: It was a quick "Hello, how are you doing, we're here."

The other type of cameo is by a celeb that plays to (or against) the public's perception of that celeb. Take Bob Saget. He's transformed himself over the years from the rather bland dad on 'Full House' and host of 'America's Funniest Home Videos' into a foul-mouthed X-rated comic. It was the X-rated, and very funny, Saget who had sex in Eric's office in season 6.