Ooh, we're talking about Harry Potter theories? To be honest, pretty much all of mine are copied from Harry Potter and the Methods of Rationality. In my mind, HPMOR is basically canon at this point. Or rather, my opinion of HP canon has just transferred from normal HP to HPMOR, which has way more logic.

One of my favorite HPMOR quotes is the following:

“That's all people think Slytherin is now, not clever planning, not trying to achieve greatness, just hating Muggleborns! I paid Morag a Sickle to ask Padma why she hadn't gone to Slytherin, we both know she got the option. And Morag told me that Padma just gave her a look and said that she wasn't Pansy Parkinson. You see? The best students with the virtues of more than one House, the students with choices, they go under the Hat thinking anywhere but Slytherin, and someone like Padma ends up in Ravenclaw. And... I think the Sorting Hat tries to maintain a balance in the Sorting, so it fills out the ranks of Slytherin with anyone who isn't repelled by all the hatred. So instead of Padma Patil, Slytherin gets Pansy Parkinson. She's not very cunning, and she's not very ambitious, but she's the sort of person who doesn't mind what Slytherin is turning into. And the more Padmas go to Ravenclaw and the more Pansies go to Slytherin, the more the process accelerates. It's destroying Slytherin House, Draco!"

It probably makes a little less sense out of context, but you hopefully get the idea.

I've done a lot of thinking about Hogwarts Houses, because I'm somewhat obsessed with personality type things. The first time I really thought hard about Houses was in comparison to true colors-- it's a personality type system with four colors: green (smart, analytical, independent), blue (empathetic, friendly), orange (energetic, spontaneous, liable to not think things through), and gold (organized, loyal). Green obviously maps to Ravenclaw, orange to Gryffindor, and blue to Hufflepuff (at least, Hufflepuff as it's generally portrayed; if you take Hufflepuff as "just and loyal and unafraid of toil," they're more gold... anyway, moving on...), but none of them map to Slytherin. If anything, Slytherin's a combination of green, orange, and gold, which always annoys me.

There's a common theory that Slytherin just exists so She Who Must Not Be Named had a place for all the evil kids. But the more reading I do in the fandom and such, the more I realize that Slytherin does actually have traits of their own. I saw a post somewhere that said, "Gryffindor: I want to be. Slytherin: I will be. Ravenclaw: I could be. Hufflepuff: I try to be." So... now I'm kind of thinking the Houses are more interesting than I'd thought... I don't know.

Ack, this got really long! Sorry and thank you, Admins!

I have a warriors theory!! SPILER ALERT FOR BROKEN CODE SERIES

So im not going too in-depth unless someone asks me to but basically Ashfur allied with the Dark Forest and they drove out StarClan, so they escaped through that Moonpool thing in StarClan(Squilf's Hope) when the real Moonpool broke, and Ashfur did too and somehow leaped into Shadowpaw's mind, and StarClan is wandering the territory as ghosts... I still haven't figured out why Tree and Rootpaw can't see them. Thoughts?

Have any of you guys ever heard of the Matrix theory? Basically it's like we're all living in a virtual reality, but we don't know it, and that's why there's little unexplained things sometimes. THE SUPERNATURAL IS A GLITCH! AUGGGH!!

However, according to all rational parts of my brain, this does not exist. 

But wouldn't it be cool if it did. . .? 

Me and my sister have a really crazy theory.

It's basically that we are all like 1000 years in the future post-apocolapse, but right before the apocolaypse scientists invented like really good VR, and we're the same person but with a wiped memory and in the past. So we're really asleep with VR headsets and bodysuits and stuff. Sound plausible?