Tonight, the 15th season of "South Park" begins its run on Comedy Central. And in typical"South Park" fashion, the premier, titled "The HumancentiPad," will use scatological humor to satirize current events and pop culture. Or, to put it another way, the show will be about iPads and poopy buttholes. But the episode, which combines Apple's iPad with the plot from The Human Centipede, is hardly the first to feature, for lack of a better phrase, "hot anal action." Since the show's inception, the anus has featured prominently in Trey Parker and Matt Stone's plot lines. With that in mind, we've compiled the nine greatest ass jokes in the history of "South Park."

Prehistoric Iceman - January 20th, 1999

In this episode, Steve Irwin (a.k.a. The Crocodile Hunter) travels around searching for animal anuses to stick his thumb into. Later in the episode, Irwin is killed, which might seem pretty insensitive, until you realize the episode aired seven years before his actual death. Of course, they did mock his death in a later episode, so I guess my point is moot.

The Death Camp of Tolerance - November 20, 2002

The subplot of this episode chronicles the adventures of Lemmiwinks, a gerbil who has been inserted into Mr. Slave's ass. The ghosts of other unfortunate animals that have perished in Mr. Slave's bowels attempt to aide Lemmiwinks in his escape.

The Entity - November 21, 2001

After his disgust with the hassles of air travel boils over, Mr. Garrison invents a new means of transportation. The only problem is, the driver of the new vehicle is forced to insert a rod up his anus. But while it may be uncomfortable, it still beats dealing with airports.

Cartman Gets an Anal Probe - August 13, 1997

This is the episode that started it all. By that I mean it's the first episode of the series, and also the first episode involving the anus. And with a title like "Cartman Gets an Anal Probe," it was easy to see where the series was headed.

Bloody Mary - December 7, 2005

"South Park" is known for it's controversial topics, but this episode involving a statue of the Virgin Mary bleeding out its ass was so controversial that the studio would not let it air uncensored out of fear of a terrorist attack. Oh, wait. It aired without editing, and no one resorted to violence. I must have mixed up my religions.

What, What (In the Butt) - April 2, 2008

In this memorable episode, Butters sings Samwell's "What What (In the Butt)" in an attempt to make a viral video. In my opinion, it's superior to the original in every way.

Spontaneous Combustion - April 14, 1999

When Kenny dies (again) from spontaneous combustion, Stan's father traces the explosion to a methane buildup. In order to mitigate the threat, the residents of South Park are then required to fart regularly. Fart jokes are always funny.

The Death of Eric Cartman - April 13, 2005

When Butters begins seeing visions of his supposedly dead friend, his parents seek medical help. Linking the visions to a traumatic event in Butters' past, the doctors set out to discover the root of the shoving a giant robot arm up his ass.

Red Hot Catholic Love - July 3, 2002

In a fitting end to a list about anal scenes, this episode features Cartman shoving food up his ass in order to crap out his mouth. In the context of the show, it's a metaphor mocking certain secularists for their condescending attitude toward religion. Out of context, it's still funny because the poop comes out their mouths.

Bonus - Tonight's Episode: The Human CentiPad