While Senators Clinton and Obama continue to slug it out for the Democratic presidential nomination, another feud -- of much longer duration, but with a much smaller war chest -- starts up again on Comedy Central.

On Sunday, March 16, at 11:30 p.m. ET/PT, "Kenny vs. Spenny" launches its fourth season, once again pitting Canadian childhood pals Kenny Hotz and Spencer "Spenny" Rice against each other in a series of bizarre and occasionally disgusting challenges. Usually, Spenny plays by the rules, while Kenny gets a little more creative (or, frankly, just cheats outright).

In the opening episode, "Who Can Handle More Torture?", the guys test their endurance for pain and humiliation, from swallowing hot sauce to having unnatural encounters with a ventriloquist's dummy and a hot dog.

Obviously, this is not a show for children.

"When we're doing the show," Rice says, "it's war. It really is."

"We actually built a trump card into the show," Hotz says. "We'll do everything in our power not to be humiliated on national television. That's really our number-one incentive in the competition.

"Spenny's more into the competition. I'm more into not being humiliated. That's my motivation."

"Kenny vs. Spenny" formerly aired in the U.S. on GSN: The Network for Games then moved late last year to Comedy Central. Along with the new season, the show adds two new executive producers, "South Park" creators Matt Stone and Trey Parker.

"Matt and Trey made [the new season] happen," says Hotz. "They caught us on Comedy Central. How it happened for Spenny is, he met me. How did it happen? I don't know: planetary alignment, luck, perseverance. We had pictures of the right people with hookers."

"This is going to be a long interview," says Rice.

"It's pretty unbelievable," Hotz continues, "that we're only now starting to happen after years of being around. Long after we thought we'd quite, we're pretty happening."

Asked how the presence of Stone and Parker has changed "Kenny vs. Spenny," Hotz says, "It's not different at all. Actually, it's really the same show."

"It's a little meaner," Rice says. "Kenny keeps getting meaner every season. Other than that, it's the same show."

"I think it's funnier," Hotz says. "The stakes are higher. We know we're talking to American audiences how. [The budget is] a little bigger. We don't really need a big budget. In fact, I'm a little worried a big budget would ruin the show."

"But don't write that," Rice says.

"It is what it is," Hotz says. "Even Matt and Trey understood it. Creatively, we totally include them in notes. We like to pick their brains because they're Matt and Trey. They're f***ing geniuses."

"They legitimize us to a certain extent," Rice says, "because we've always known the show is right, and they've always known the show is great. But I remember there was an executive, I won't say his name, and he said that our show was the worst show in the history of television -- and he wasn't kidding."

"Your dad wasn't an executive, Spenny," Hotz says.

"And there was a satisfaction," Rice continues, "that I got from [Stone and Parker] putting their stamp of approval on it, and the numbers are great. It's very satisfying."

"Out of the entire planet," Hotz says, "they're our smartest, funniest fans."

And, believe it or not, despite their on-screen animosity, Hotz and Rice are truly pals off-screen.

"We're natural opposites," Rice says. "So we're like a real-life comedy duo in that sense. I'm sort of the straight man in that I'm ethical, and I play by the rules, and he's the crazy man who will do anything to win. So a lot of the planets were aligned in our lives, having known each other for so long.

"People say, 'How can you guys be friends?' We're like family. Our fathers were friends. We've just known each other from forever."

It's that contrast, Rice and Hotz believe, that helps broaden their fan base.

"Ultimately," Rice says, "which is why the show is successful, is the audience indentifies with one of us. There's a legion of Kenny fans out there who love it when he does what he calls 'thinking out of the box,' what I like to call cheating. Whatever."

"And the three Spenny fans," Hotz says.

"And then there's the three Spenny fans," says Rice.