Namely: John, Teyla and Ronon start hooking up because they are totally boning out over Rodney all the time.
You know, Ronon walks in on John jerking off and saying Rodney's name, so they start hooking up, but they mostly talk about Rodney's thighs and revel in the McKay hotness together. At some point, they find out Teyla is of the same mind, and the three of them start having hot sex fuelled by MCKAY MCKAY RODNEYYYYYY.
Rodney, of course, at some point figures it out-- except for the part where all three are hot for him. He just thinks they don't want him in their teamsex shenanigans! He doesn't meet the sexy standard! This would lead to him becoming increasingly withdrawn and miserable (my favorite!) because he thinks they all laugh about how fat and gross he is after having athletic, hooray for guns-type sex. At some point offworld, he gets pushed into a river by a cheerful native, and when he finally gets out, the other three have disappeared, leaving him COLD and WET and ALONE. (They have, of course, hastily departed to grope each other with the recent image of his clinging wet shirt freshly in their minds.)
So at some point, they find out that he knows-- but also that he thinks he just wasn't invited!!!! Which leads to them sort of shyly asking him to join them (because, hello, asking your mutual crush to join your group sex is nervousmaking), but he thinks it's PITY, obvs. And AFTER, oh man, AFTER, he wakes up in the middle of the night, and the other three are all piled in a heap on the other side of the bed, tears tears! (This is of course because they are all used to sleeping together in a pile and they are still worried Rodney will freak out if they snuggle him too much, but he doesn't knowwwwwwwwwwwwww!!!)
So he slips out of bed in the dark dark night, HUMILIATED, MISERABLE, WOE WOE WOE, and in the morning they think he was all BORED and NOT INTO IT and everyone is sad.
Whatever, eventually they convince him of their sincerity, probably preceded by a scene where someone almost dies because I'm into that, and having Rodney around means that the other three can realize they also love each other, or something. I dunno. THE END!!!!
(so we're clear, I'm totally NOT making fun of the genre-- I just think that all genres should have stories where Rodney thinks everyone hates him.)
Oh, um, my original conception also had a bitter divorcée named Denise who works in the mess hall. She commiserates with Rodney over people who only want sexual partners with perfectly toned abs, and she gives John gristle-filled pieces of meat at dinner, which he pokes at sadly and with great confusion. Then later when Rodney is happy she fills all four of their plates with deliciousness at every meal! HOORAYYYYYY!