And yet, here it is - the Cracktastic!Crossover Pairings Database.
Alec McDowell (Dark Angel) and Caprica Six (Battlestar Galactica)
Only engineering could bring two so beautiful into the world. They've both sinned and repented, in their own ways, with respective rehabilitations brought on by doomed love that was against orders and in direct conflict with a mission. Oh the similarities. Beyond that, both use bodies to mask their brains, and have no shame in doing so. Both revel in being a superior species and take their inhuman abilities for granted. They're incredibly narcissistic, but have soft spots they try like hell to hide, and buttons better left un-pushed. And yet, they'd clash in the face of faith, since... well, Alec has none (and let's not forget, his twin did commit a series of gruesome murders in the name of belief). The ultimate in het cracktastic pairings.
Oliver Queen and Lucas Luthor (Smallville)
And here we have their slash counterparts. I'm not much of a slash girl (I just can't see it in most of my fandom men), but even I've read some truly cracktastic slash (think Lex Luthor and Firefly's Simon Tam). That one worked amazingly well, but this duo takes the cake. Let's face it - Smallville is the mecca of all things boy/boy, and these two are the best of the bunch. Not only are they billionaire playboys with orphan issues (Ollie's parents are dead, and Lucas' living parental unit doesn't really give a damn), but they both despise Lex. Hell, they'd get involved for that reason alone - it'd drive big brother crazy. Add to that the air of ruthlessness that both carry like a shield, and this is a pairing made in slash heaven. Let's not even mention the hotness factor. Well, okay, let's.
Malcolm Reynolds (Firefly) and Kara Thrace (Battlestar Galactica)
Enough ghosts between them to suffocate the living and breathing. Her Cylons are his Alliance, and they're still so haunted - and on some level, they both like it that way. There's always someone to battle, so their hands - and their guns - are never idle. And neither is more at home anywhere than in the air, in their ship, in control. It'd be interesting to see who gave the orders, and who ended up on top.
Sam Winchester (Supernatural) and Chloe Sullivan (Smallville)
Yeah, I'm completely smitten with this pairing already. He's haunted by lost love, she's hung up on love that was never found. But the searcher in her and the savior in him just wouldn't be able to resist. She'd want to help him find answers (because that's what she does), and he'd want to keep her safe (because that's how his mind works). Sam's not the anti-Clark that Jimmy is - in fact, he's got a lot of the same qualities she loves about Clark, without the same hangups. Not that Sam doesn't have his own. They've both got absentee mommy issues, to say the least. Nevermind that they could both be ticking time bombs, counting down toward superpowered self-destruction. Oh, the possibilities. I love it. It must be written.
Michael Guerin (Roswell) and Sharon Valerii (Battlestar Galactica)
Athena obviously belongs to Helo, but Boomer is up for grabs. She and Michael are two sides of the same coin - he's half alien and wishes he were more, she's a machine who wishes she were human. They're both soldiers, both fiercely loyal, stubbornly determined, and more than a little bit lost. And hello, human-alien-Cylon baby possibilities. I think they're a match made in sci-fi heaven.
Spike (Angel) and River Tam (Serenity)
I made the distinction because, in a lot of ways, they're both wildly different characters beyond thier core fandoms. Post-Serenity River has been to Miranda, she's unleashed the inner weapon, and she's emerged on the other side in tact. Spike has died, been a ghost, saved the world. She lived without a whole brian, he loved without a soul. And you know he's a sucker for warrior women and little girls lost (not to mention women with questionable mental health) - she's a package deal.
It'll be updated periodically, whenever my brain spits out more insane combinations (and if I get around to actually writing some of these, I'll link the fics from the entry). Have a Cracktastic Crossover Pairing of your very own? Leave the who and the why, and I'll weigh in.