A meme taken from the The Muppet Show on television. In case you're a newfag (and a newborn), the show's premise was a vaudeville-like theatre, with puppets and marionettes as performers and celebrity guest-stars. Up in the theatre's high-class balcony seats were two old men, Statler and Waldorf, who would heckle and jeer at everything and laugh at their own heckling with a distinctive chuckle.
Using this routine in the context of /tg/ began when a DM managed to crowbar in a Statler and Waldorf pair into a colosseum where the player characters were fighting. The DM just lifted lines straight from The Muppet Show ("never did stealing quotes feel so good"), and his players somehow managed to restrain themselves from choking the living shit out of him.
Some examples:
"Well, that fight was different."
"Did you like it?"
"No."
"Then it wasn't different!"
"DOHOHOHOHO!
*After a fumble*
"Well, you gotta give him credit."
"Why's that?"
"He's gonna keep on trying until he succeeds."
"DOHOHOHO!"
"I call that a medium maneuver."
"A medium maneuver?"
"Yeah. It wasn't rare, and it definitely wasn't well done!"
"DOHOHOHO!
*One of the fighters loses their cool and fires an arrow at them in the stands*
"Looks like that boy was trying to make a point."
"Shame it went right over our heads!"
"DOHOHOHO!"
"I hate spells with a long casting time."
"Why's that?"
"It makes this fight take longer."
"DOHOHOHOHOHOHO!"
"I wish I didn't succeed on my Spot check."
"Why?"
"Now I actually have to see the fight."
"DOHOHOHOHOHO!"
"You old fool! You slept through the fight!"
"Who's the fool? You watched it!"
"DOHOHOHOHOHOHOHO!"
"There's nothing like good combat."
"Yup, and that was nothing like good combat."
"DOHOHOHOHO!
"I wonder if that bard can sing tenor."
"Tenor?"
"Yeah, ten or eleven miles away."
"DOHOHOHOHOHO!"
"Looks like that Wizard cast Sleep down there."
"I wish he'd cast it up here too!"
"DOHOHOHOHOHO!"
"You know what would be great? If we were mages."
"Yeah. We could summon better combatants!"
"DOHOHOHOHOHO!"
"Hey look, it's a half-elf."
"What's the other half?"
"Not good at fighting, that's for sure."
"DOHOHOHOHO!"
"I don't envy that Mind Flayer."
"Why?"
"He isn't going to have a lot to flay down there!"
"DOHOHOHOHOHOHOHO!"
"So, is that Paladin lawful good?"
"I don't know about lawful, be he sure isn't good."
"DOHOHOHOHOHO!"
"Hey, wake up or you'll miss the best part of the article!"
