A marriage of voices
Sam (Kurt, Quinn); Implied/suggested Sam/Kurt and Sam/Quinn; Someone the world deems more appropriate.
Note: Set in Duets. No mentions of any events before or after that episode.

"Welcome to Glee club, lady lips."
Sam feels the slushie in his face before they ever say a word. It's cold and unexpected, like someone stuck their hand in ice for a little while before suddenly deciding to slap him with it. Admittedly he probably could come up with a better comparison. He feels a hand on his shoulder, he turns his head and sees Quinn.
"Close your eyes," she tells him, "you don't want to get slushie in them." So he closes his eyes and follows her where she leads him.

Kurt has a nice voice. Sam listened to the MP3s Kurt sent him - not all of them of course because he feels like that might make him a bit obsessive - and he really likes his voice. He likes his voice and he wants to sing with him. Things don't always work out how Sam wants them to. Glee club doesn't make his high school life any easier, Finn isn't as popular as one may originally assume and Kurt Hummel doesn't think Sam Evans is good enough to sing with him. Well, at least that's how Sam takes it at first. Kurt tells him to sing with someone the world deems more appropriate and he does; he goes out and he finds the perfect partner. Quinn Fabray is blonde, female and the head cheerleader. She fits the role perfectly; he couldn't have asked for a better partner.
If he says those words with the slightest hint of harmful intentions then no one else really has to know. Sometimes Sam can't stop himself from saying things he shouldn't when he's upset. The truth is, Sam is upset, he thought Kurt wanted to sing with him and now he's not really sure.
Maybe he's upset because he wanted to sing with him too.