Sam, Dean, pretty much gen, although some cracktastic, non-gen mental images? :D
"Oh my god," Dean said. It was the same tone he'd used when Sam had showed him that Photoshopped picture of Britney Spears with the snake: half-horrified and half-intrigued. "Are you looking at kiddie porn?"
"No!" Sam yelped, hugging the laptop to his chest and shooting Dean a glare. He cleared his throat, and continued in a calm tone, although his face was bright red: "I was just reading this thread about how LiveJournal is banning controversial artwork from their site. I wanted to see what the artwork was that they decided to ban."
Dean stared at him. "'Thread?' 'LiveJournal?' Sam, did you forget our conversation about how I don't talk Geek?" There was a pause, and Sam opened his mouth to explain further, but Dean interrupted. "And anyway, I don't see how there's anything controversial about kiddie porn. Lemme see." He made a snatch for the laptop, and Sam was surprised enough that he was able to wrest it away. He opened the lid and stared at the screen.
Sam cleared his throat and his face, if possible, turned even more red.
Dean started laughing. "Oh my God, it's not just kiddie porn, it's kiddie porn of Harry Potter!"
Sam scowled and made a grab for the laptop. "It is not kiddie porn, Dean. Jesus. He has pubic hair, for Chrissakes."
Dean arched an eyebrow, infuriating smirk firmly in place. "Sammy, are you in denial? Have any 'unnatural urges' you want to talk about? It's okay, you know, I'm here for you."
"Oh my God, shut up," Sam moaned, closing his eyes and slumping in his seat.
"If you think it would help to act out your fantasies, we could always do the role-playing thing. You know, you could be the big, mean professor and I could wear a tie and play the part of the helpless schoolboy ..." Dean had switched to his taunting tone, the one he used to use when Sam was still an awkward fourteen-year-old and couldn't get a date to save his life.
"You are so sick," Sam informed him, cracking his eyes open to glare at Dean.
"'Oh, Professor,'" Dean shrilled in falsetto, "'are you going to discipline me now with your big, hard wand?'"
Sam lurched to his feet with a growl. "Put the laptop down now."
Dean smiled at him innocently. "Why?"
"Because I don't want it to get broken when I can kick your annoying ass all over this shitty little room."
The smile cranked up a notch to become a shit-eating grin, and Dean set the laptop on the table with exaggerated care. He took a step back from the table and spread his arms. "Bring it on, baby brother."
"You are so dead," Sam said and launched himself at Dean.
Dean was still laughing when the first punch landed square in his eye.